Breastfeeding is usually strongly recommended by doctors; it is by far and away the best and most convenient way to feed a baby.  Not only will the baby be healthier, but it also helps the new mother lose weight more easily.  Calories are burned during milk production; indeed some of the weight gained by a woman during pregnancy is intended to be used during lactation.  Breastfeeding also releases a hormone in the woman's body that acts as a natural tranquillizer, filling the mother with a sense of calm and well-being while she is breastfeeding.

No authoritative medical studies seem to have been conducted on the maternal desires and instincts of transwomen.  But it seems safe to claim that a substantial proportion of at least  younger transwomen would like to be a mother and breastfeed a baby.

Nursing and Transwomen

While almost all transsexual women proudly regard their breasts as an important sign of their femininity and womanhood, until recently few really consider their primary biological purpose. 

However, in 2005 an English newspaper published a story about a young woman breastfeeding her baby in a restaurant, she was asked to leave and wasn't at all happy about that.  Not really headline material, but readers then discovered that the woman in question was a male-to-female transsexual.  As a 'husband', she had begun female hormone treatment at about the same time as his/her wife had become pregnant.  After the baby's birth, the transwoman had acupuncture to help kick-in her own milk production and was sharing nursing duties with her former wife.  

30-year old Mika Minio-Paluello breastfeeding her baby

This story was inevitably intended to be rather sensationalist, but some transsexual women reading it were probably surprised to learn that their breasts might be capable of performing the function that they were intended for by nature.

Since then an increasing number of transwomen have realised from articles (including this website!) that is possible for them to breastfeed.  Statements by anti-transwomen campaigners such as Milli Hill's "Male people, however they identify or describe themselves, cannot breastfeed” are factually incorrect.

In September 2022  the online magazine INSIDER published a contraversal article desrcibing how Some Parents Are Breastfeeding Without Pregnancy or Giving Birth.

Another example is Mika Minio-Paluello, who identifies as a transgender woman and a lesbian, although still pre-GCS.  In 2023 she published on Twitter a photo of her breastfeeding a baby born by her partner, hinting that IVF had been used.  She had taken hormones and drugs to enable lacation and helped breastfeed the baby for a few weeks before sadly getting a cancer diagnosis that stopped this.  The story was picked up by a UK television channel and she featured in a news item, causing considerable controversy about the ethics of a "man" breastfeeding.  She was even reported to the National Society for the Prevention of Cruelty to Children (NSPCC), who quickly concluded that there was no risk to the child.

Physical Requirements

The breasts of a transsexual woman are quite capable of producing milk ("lactation") given the following circumstances:

1. The breast has not been badly damaged internally, e.g. by breast augmentation
2. The breast has a sufficiently well-developed internal structure, often requiring a year or more of hormone treatment
3. There are suitable stimuli (physical, hormonal, psychological) to start and then maintain the production of milk
4. There's a functional pituitary gland [Closely linked with point 3]
5. The woman is in reasonably good health - a sick or very poorly fed body won't waste energy and nutrition on producing milk.

The female hormones taken by transsexual women induce breast development ranging from the slight to the generous, but with a bias towards the lower end. Typically their breasts appear unsatisfactorily small and about 50% of transsexual women have breast augmentations.  However even very small breasts can often function as nature intended, i.e. feed a baby.  Breast augmentation, common in transsexual women, does not normally prevent breastfeeding. 

The main reason that breastfeeding may not be recommended or encouraged by the physician is if the drugs and other hormones being taken may make the milk unsuitable for nursing. Once the baby is born, the transsexual mother may well be able to experience the final physical act of pregnancy and birth and attempt to nurse her new baby - albeit with many assumptions such as being well enough after the delivery and her breasts are adequately developed and haven't been badly damaged by augmentation.  There are already a few instances of transsexual women lactating and even breastfeeding the babies of ex-wives or female partners.

Motivation

After millions of breast augmentation procedures using silicone implants, there is no evidence that the silicone leaks into breast milk, and even if it did there is no evidence that it would then harm the baby. For example, a silicone-based medication, Simethicone, is used to treat a baby's stomach gas.

In order to be able to produce milk internally the breast must have certain structures in place, but fortunately these are present at birth in every human, whether genetically male or female.   It's also worth noting that highly visible factors such as breast size and areola diameter that are often of great importance to transsexual women in fact have relatively little effect on the breasts potential ability to lactate and the quantity and quality of the milk that will be produced.  Whatever the size of her breasts, a M2F transsexual woman can still potentially breastfeed if the internal structures are in place and undamaged.

Mammogenesis commences at puberty with the onset of oestrogen secretion by the ovaries, usually between the ages of 10 and 12 in the girl.  Oestrogen causes enlargement of the mammary fat pad, one of the most oestrogen-sensitive tissues in the human body, as well as lengthening and branching of the mammary ducts.  About 40% of male children also initiate mammary development during puberty due to the tendency of the testis to secrete significant quantities of oestrogens in early phases of its development.  As testosterone secretion increases this function is lost.

Oestrogen stimulates breast growth by acting on the mammary tissue.   With the onset of the menstrual cycle the presence of progesterone stimulates the partial development of mammary alveoli, so that by the age of 20 the mammary gland in the woman who has not been pregnant consists of a fat pad through which course 10 to 15 long branching ducts, terminating in grape-like bunches of mammary alveoli.  In the absence of pregnancy the gland maintains this structure until menopause.

Mammogenesis is completed during pregnancy, with the gland becoming able to secrete milk sometime after mid-pregnancy.  

Lactogenesis (referred to as the time when the milk "comes in") starts about 40 hours after birth of the infant and is largely complete within five days. 

When nursing has ceased the gland undergoes partial involution, losing many of its milk producing cells and structures, a process which is only completed after menopause. 

Breast Development in the Transsexual Woman
A combination of supportive tissue, milk glands, and protective fat makes up a large portion of every woman's breasts (or mammary glands).  Every person is born with milk ducts — a network of canals that transport milk through the breasts — present from birth.  In the male-to-female transsexual woman the mammary glands stay quiet until commencing female hormone treatment releases a flood of oestrogens in the body in what's effectively a female puberty - thus initiating the first phase of mammogenesis and causing the breasts to grow and swell.

The amount of hormone induced breast development achieved in the genetically XY male transsexual woman is very age dependent.  Young boy-to-girls who start female treatment during their normal puberty years (i.e. about age 12-16) are likely to reach near normal breast development.  But unfortunately the amount of development that can be expected rapidly tails off as the age of the commencement of hormone increases, and older transsexual women will commonly suffer from underdeveloped (hypoplastic) breasts. 

Breast development is categorised by the "Tanner Stages" scale which goes from I to V.  It can again be emphasized that there is really NO minimum degree of breast development in order to be able to lactate; there are well documented instances of even men with minimal Tanner I breasts producing some milk and breastfeeding without using hormones.  On the other hand there is no doubt that the higher the development stage, the easier it will usually be to start lactation and the greater the likely quantity of milk produced.  In general, well-developed Tanner IV or V type breasts are really required for successful nursing of a baby, perhaps a majority of the girls who start hormone treatment by age 25 are likely to achieve this but most older woman will achieve no more than Tanner III or even II breast development.  Such hypoplastic breasts are very small or narrow, lack normal fullness, and may seem bulbous or swollen at the tip.  They are also likely to be widely spaced and one breast may be larger than the other.  Hypoplastic breasts don't develop and grow in response to any additional hormones given in order to simulate pregnancy and prepare the breast for lactation.  Breasts of this kind have fewer milk glands than normal, leading to milk-production problems.  

Breast Development During Pregnancy

It is necessary to understand how the human breast develops and prepares for milk production during a woman's pregnancy.  

Mammogenesis is completed during pregnancy - indeed pregnancy is the period of greatest mammary growth.  Extensive lobular and alveolar development occurs only during pregnancy, also milk secretory cells only develop during pregnancy, therefore this period is extremely important in determining the number of secretory cells in the lactating gland and the subsequent production of milk.  Mammary growth (of the mother) accelerates throughout pregnancy and is fastest during the later stages of pregnancy, which coincides with the most rapid period of foetal growth. 

Breast Structure of a Pregnant Woman
A pregnant woman will certainly notice a huge metamorphosis occurring in her bra cups. These physical changes include:

• tender, swollen breasts
• darkened nipples and areolas (the circle of skin surrounding the nipple)
• the appearance of tiny bumps around the areola called the Glands of Montgomery

But perhaps even more remarkable than this visible transformation are the extensive changes taking place inside her breasts, primarily under the stimulation of high levels of oestrogen and progesterone, combined with the rising levels of prolactin from the pituitary and human placental lactogen (HPL) from the placenta. 

Progesterone and Oestrogen blood plasma levels rise steadily during pregnancy.

Nestled amid the breasts fat cells and glandular tissue is an intricate network of channels or canals called milk ducts.  The additional hormones released during pregnancy cause the cells of the mammary fat pad to diminish in size and their place is taken by the developing ducts and alveoli. 

Milk is produced inside the alveoli, which are surrounded by tiny muscles that squeeze the glands and push milk out into the ductules.  Those ductules lead to a bigger duct that widens into a milk pool or milk sinus directly beneath the areola.  Milk pools (also known as sinus) act as reservoirs that hold milk until a baby suckles it through tiny openings in the nipple.   Essentially the 15 or 20 milk ducts act as individual straws that all end at the tip of the nipple and deliver milk into a baby's mouth. 

The mammary gland becomes able to secrete milk sometime after mid-pregnancy, and begins to produce small amounts of a protein- and fat-rich secretion sometimes referred to as precolostrum.  It seems likely that mammary development continues through the duration of pregnancy since milk secretion by mothers of premature infants often appears to be diminished.  The onset of copious milk secretion (or lactogenesis) is held in check by the high levels of circulating progesterone until after childbirth. 

A woman's breasts enlarge and the areolas become darker
and more prominent during pregnancy

Differentiation of the breast to its mature status occurs by the third month of pregnancy, although it will take about 6 months for the breast system to fully develop and become functional for lactation.  Indeed, mammary growth will continue right up to birth, and even after if nursing.  In a pregnant woman, by time the baby is born, glandular tissue has replaced most of the fat cells and accounts for the much-enlarged breast.  The increase in size varies greatly with the individual, ranging from zero to 800 cc of volume (and 1½ lb of weight!) per breast; the average being about 400 cc.  It is normal for women to increase by one or two cup sizes during pregnancy, although this will decline (sometimes dramatically) after the cessation of lactation.

Oestrogen and Progesterone

Optimal mammary growth requires both oestrogen and progesterone hormones.  Together, these result in growth of the lobular and alveolar system.  Both hormones are elevated during pregnancy, which is why there is no such "lobuloalveolar" growth during a woman's oestrus (fertility) cycle, when only one of these hormones is elevated at a time.  Progesterone is elevated throughout gestation (required for maintenance of pregnancy), while oestrogen is particularly elevated during the second half of gestation.  Consequently, most of the mammary growth during the first half of gestation is mainly ductal growth and lobular formation.  In the second half of gestation, ductal growth continues, but most growth is lobuloalveolar. Oestrogen and progesterone together establish the conditions needed for geometric cell multiplication to occur. For example, from one original cell, 8 cell divisions yields 128 cells.

During pregnancy, the mammary tissue has oestrogen receptors and progesterone receptors. During lactation the mammary gland has oestrogen receptors, but not progesterone receptors.

Other hormones

As well as the oestrogen and progesterone hormones well known to transsexual women, there are several other hormones important to breast development and milk production.  Indeed, mammary development in the pregnant woman takes place under the influence of an extraordinarily complex mix of hormones, including:-  prolactin, human placental lactogen, estradiol (a type of oestrogen), progesterone, insulin, cortisol, growth hormone, thyroid hormones ...

Prolactin is a protein hormone secreted from the anterior pituitary gland, as well as assisting in breast development; it stimulates and controls the actual production of milk. 

In a pregnant woman, the placenta produces an important hormone called Human Placental Lactogen (HPL) which adjusts the maternal metabolism.  One of its functions is similar to prolactin, i.e. stimulation of milk production by the mammary glands.  HPL seems to work with oestrogen and progesterone to increase the number of alveoli in mammary glands and also plays a role in making the alveoli functional (capable of producing milk).  It's thought that the level of HPL hormone activity in the maternal blood regulates the extent of mammary development during late pregnancy.  HPL also causes the secretion of a form of milk called colostrum from about the fifth month of pregnancy. 

Yet another, and apparently unimportant, hormone is secreted by the pituitary gland of a pregnant woman, Melanocyte Stimulating Hormone (MSH).  Its only known effect is to stimulate the skin to produce pigmentation, causing the aeroli to enlarge and darken. 

 

Milk Production in a Maternal Mother

Lactogenesis
In a human mother lactogenesis, or the onset of copious milk secretion, (also referred to as the time when the milk "comes in") starts about 40-48 hours after childbirth and is largely complete within five days.  Milk secreted during the period between colostrum secretion and mature milk is called transition milk.  

Lactogenesis is associated with an abrupt increase in milk volume secretion, which goes from a mean of about 50 ml per day on day 2 of lactation to about 500 ml per day on day 4.  After this time there is a gradual volume increase to about 850 ml/day by three months postpartum. There are also profound changes in milk composition during the early post childbirth period as the production of milk products comes into high gear.  By 10 days after childbirth the milk has assumed the composition characteristic of mature milk. There are minor composition changes that continue throughout lactation.  Full lactation, or the secretion of mature milk, continues as long as the demand is there, up to three to four years for infants in some cultures.

Three factors are necessary for successful lactogenesis: a developed mammary gland, continued high plasma prolactin levels, and a fall in progesterone and oestrogen levels that otherwise inhibit lactation - it can therefore be partially inhibited by high doses of oestrogen.  It is important to note that the milk "comes in" at the same rate whether the infant suckles during the first 48 hours or not.  Thus the onset of milk secretion depends, not on milk removal from the breast, but on the changes in hormonal status associated with child birth.  However, continued milk secretion depends on milk removal from the breast, the involutional process sets in after only 3 to 4 days if breast-feeding is not initiated.

 

Breast Stimulation in the Transsexual Woman

Hormonal Stimulation

Lacking the hormone producing ovaries and placenta present in a pregnant woman, the transsexual woman attempting to induce lactation must take oestrogen by some artificial means (oral, injection, patches, etc.).  The oestrogen is then abruptly withdrawn to mimic the rapid hormonal changes following delivery. 

It is appropriate at this point to distinguish between trying to achieve some slight lactation, ranging from a few drops up to as much as 35% that of a nursing mother, and trying to achieve full and copious milk production as the primary sorice of nutrient for a baby.  Both require some degree of hormonal stimulation, but it's a case of for how long, and also how well the breasts respond to the hormonal stimulation.

If only a minimal degree of lactation is being attempted then the high oestrogen regimen may be as short as two weeks.  But if full lactation is desired, then the transsexual woman must try to induce all the necessary developmental changes in her breasts by simulating a full period pregnancy by taking high doses of oestrogen and progesterone hormones for a period of at least six months (probably not coincidently, a premature baby born after the 28th week or sixth month of pregnancy is "viable" and will often survive, and will thus require feeding).  This sustained hormone treatment may stimulate her breast in to developing and preparing for lactation, but unfortunately transsexual women with underdeveloped hypoplastic breasts are unlikely to succeed in this endeavour as their breasts will fail to respond to the additional hormones.

Transwoman Gloria with baby Grace.  Probably but not certainly staged.

Also, in a pregnant woman her production of the estriol type of oestrogen greatly increases and it becomes the dominant type of oestrogen in her body.  When present in high levels (unlike the non-pregnant lower levels), one of its effects is to help prepare the breast for milk production.  However, the "weak" estriol oestrogen is rarely taken by transsexual women as part of their hormone therapy, instead standard oestrogen prescriptions are either of the estradiol (e.g. the Estrace brand) or estrone (e.g. the popular Premarin brand) types.  Unfortunately, prolonged taking of large doses of these "strong" oestrogen types, as is common with transsexual women, seems to de-sensitise the body to estriol, making stimulating the breast to prepare for lactation via hormones much more difficult.

Assuming that the hormones have an effect, the period of the most visible breast growth is often during the first eight weeks of treatment.  This enlargement is potentially just temporary as it's primarily due to engorgement of the blood vessels, enabling increased circulation to the breasts.  Thereafter, oestrogen hormones stimulate cell mitosis and growth of the ductal system, the development and differentiation of the glandular tissue (lobules and alveoli) is dependent on progesterone, whilst breast fat accretion seems to require both. 

Regarding other hormones found in pregnant woman:

• Prolactin may be produced naturally by the woman's pituitary gland which is helpful but probably insufficient.  Currently, there is no prolactin medication on the market but prolactin-inducing drugs are readily available and these can be taken to increase  prolactin production to normal levels. 
• HPL is valuable aid to breast development and lactation, but it's not naturally produced in the body of a transsexual woman.  Highly purified HPL is available as a medication but unfortunately it's hard to obtain, very expensive (a course would cost several hundred dollars a day), and is very rarely used as a medication.
• MSH is not believed to be necessary for lactation and is unlikely to be present in a transsexual woman.

Hand-pumps are a very cheap mechanical aid to help stimulate lactation, but they are not suitable for prolonged heavy use.

Mechanical Stimulation
If it not possible to take additional female hormones in order to stimulate the breasts in to preparing for lactation, or if (as is commonly the case) the hormones have no effect due to hyperplasic breasts, all is still not lost.  This is because prolactin and oxytocin, the hormones which govern lactation, are pituitary, not ovarian (or "female") hormones.  Both prolactin, the milk-making hormone, and oxytocin, the milk-releasing hormone, are produced in response to nipple stimulation. 

Most genetic women and some men can induce lactation to some extent with only mechanical stimulation.  This consists of breast massage, nipple manipulation, and sucking - the later either by a baby or by expressing using a good quality electric breast pump with a double pump kit.  Realistically expression by hand, or even with a hand pump, is simply not a practical alternative to an electric double breast pump given the frequent and prolonged sucking required on each breast.

A possible expressing regime: Begin by expressing each breast for about five minutes, three times a day.  Increase the length of the pumping session as you become more comfortable, until you are expressing for a total of about 15 to 20 minutes on each breast every two to three hours during the day.  Expressing both breasts simultaneously by double-pumping obviously saves a lot of time every day by this point!  You must include nighttime pumping sessions, allowing just one long 4-5 hours period of sleep.

Constant expressing will soon get to become hard work, when after a week you still haven't seen any milk at all, try not to become discouraged or concerned, unfortunately it may well take four to six weeks for the breasts to begin producing milk this way.  Some dedicated women have reported only finally achieving some success after two or three months pumping!

Stress, tension, and fatigue all produce hormones that can reduce let-down.  Avoid smoking and excessive alcohol and caffeine - these are known to inhibit a mother's milk production and let-down. 

To pump effectively and increase milk supply it is essential to relax and stimulate as much as possible the milk let-down response crucial to milk expression.  Suitable mental or environmental stimuli such as baby photo's, imagining yourself breastfeeding, direct sucking stimulation of the nipples and immediately surrounding tissue, playing a tape of the cries of a hungry baby, ... etc,  are essential aids to milk production.  And a partner can greatly assist with sexually arousing mental stimulation and manual manipulation of the woman's body before, and even during, her expression period.

A good example is Yvette (left).  In the early 2000's she was determined - albeit with little professional medcal help - to breastfeed the baby being carried by her partner.  She researched the options and based on the limited information then available, eventually decided that breast pumping was the best option.  She says:

"Around 20 weeks out from our baby’s due date ... I begin with a schedule of four hourly pumpings, beginning with 5 minutes each side and increasing after a fortnight to 10 minutes each side. About four weeks in .., I was beginning to feel discouraged I put my bra on one morning and noticed it was a little tighter than usual. Taking it off and looking in the mirror and discovered that my breasts were discernibly heavy. ... By the time I reached the last four weeks of my partner’s pregnancy, I was pumping about 50 – 60mls in total at each session.  When my daughter arrived at 40 weeks I was able to give her very first feed. I can’t express to you the joy I felt at that moment, but perhaps you can see it in my face in the picture attached to this article."

Yvette soon had supply issues as the baby’s needs sped ahead of her only slowly increasing milk production.  However, in the early months her partner expressed breast milk which they stored, and Yvette used this to fill a Supplemental Feeding System, before the introduction of solids eliminated the need to use this.  Yvette finally ceased breastfeeding her daughter when she was 18 months old.

Expressing by Hand Breast massage - place one hand underneath your breast, the other on top.  Slide the palm of one or both hands from the chest gently towards the nipple and apply mild pressure.  Rotate your hands around the breast and repeat in order to reach all the milk ducts.