What Does Normal Breast Development Actually Look Like?
Understanding conical breasts, Tanner stages, and what gender-affirming care means for how breasts grow.
One of the questions I receive most often, from trans women, from parents of trans young people, and from people who are simply curious about their own bodies, is about breast shape. Specifically, people want to know whether a conical or pointed breast shape is normal, whether it means development has not finished, and what it might mean for someone who is taking gender-affirming hormones. It is a really important question, and it deserves a thoughtful, evidence-based answer, because there is a lot of confusion out there and quite a bit of unnecessary worry.
So let me walk you through what the science actually tells us, covering how breasts develop in everyone, what a conical shape means, and what trans women and trans young people can expect when oestrogen is part of their care.
The Five Stages of Breast Development
Breast development follows a well-established sequence that was described by Professor James Tanner in the 1960s and has been used in clinical practice ever since. These five Tanner stages give us a shared language for understanding where someone is in the process of development, and they apply whether that development is happening because of natural puberty or because of gender-affirming hormone therapy.
Stage 1 is the pre-pubertal stage, where the chest is flat and no breast tissue has yet formed. Stage 2 is the beginning of development, when breast buds appear as small, firm mounds beneath the nipple and areola. This is usually when tenderness and some itching begin, as the tissue starts to grow. Stage 3 is when the breasts begin to enlarge more noticeably, with the glandular tissue and fatty tissue both increasing. At this stage, the shape is often described as conical or pointed rather than round. Stage 4 brings a further projection of the nipple and areola, which form what is sometimes described as a secondary mound on top of the breast. Stage 5 is the mature stage, where the breast takes on a rounder, fuller shape and the areola settles back flush with the breast contour.
The key thing to understand here is that the conical shape at Stage 3 is entirely normal. It is not a sign that something has gone wrong. It is simply where most people sit for a period of time during their development, and for many people, including many cisgender women, it can feel like quite a long wait before the breast rounds out into its adult shape.
When the Conical Shape Stays
For most people going through a typical female puberty, development progresses through all five Tanner stages over several years, with the breasts becoming rounder and fuller as time passes. The whole process from the first breast bud to full maturity can take anywhere from two to five years, and it is not unusual for development to feel uneven or asymmetrical along the way.
For some cisgender women, however, the breasts do not round out as fully as expected. This is sometimes described as tubular or tuberous breast shape, and it happens when the connective tissue around the base of the breast restricts the normal outward expansion of breast tissue. The breast stays narrower at the base and retains more of a conical or elongated appearance. This is a variation in development rather than a disease, and while it can cause real emotional distress and body image difficulties, it does not represent a health risk.
It is worth noting because many trans women and trans girls describe a shape that sounds very similar, and understanding the underlying biology helps make sense of what is happening and why.
Breast Development in Trans Women on Oestrogen
When a trans woman begins gender-affirming hormone therapy, her breast development follows the same Tanner stages as in cisgender puberty. The tissue that develops is anatomically and histologically identical to that of cisgender women, including the formation of lobules and ducts. This is not some approximation of female breast tissue: it is female breast tissue, responding to female hormones.
The timeline is also similar to natural puberty. Breast buds typically become palpable beneath the areola within three to six months of starting oestrogen, and most of the growth that will occur takes place within the first two years of treatment. One large prospective study involving 229 trans women across European gender clinics found that the main period of breast growth occurred within the first six months of hormone therapy, with the development curve flattening out after that.
The most important thing to understand about breast development in trans women, though, is that many trans women plateau at Tanner Stage 3. This is the conical or pointed stage. Most trans women are unlikely to reach Tanner Stage 5 through hormone therapy alone, without surgical augmentation. Research consistently shows that breast volume in trans women, while real and meaningful, tends to be smaller than in many cisgender women. A prospective multicenter study found that after one year of hormone therapy, nearly half of participants had a bra cup size of less than an AAA cup, with only around ten percent reaching an A cup or larger.
There are several reasons for this. One is that exposure to testosterone during male puberty may induce structural changes that limit how fully breast tissue subsequently develops in response to oestrogen. Another is that the wider ribcage and shoulder structure that many trans women have means that even where breast volume is comparable to that of many cisgender women, the breasts may appear smaller because they are distributed across a broader frame.
This is not a failure of treatment. It is simply biology, and it is something that every trans woman deserves to know about and be supported through, rather than being left to discover it on her own with no context.
What About Oestrogen Dose and Timing?
One question that comes up regularly is whether taking a higher dose of oestrogen will result in more breast growth. The evidence here is actually quite nuanced. Several studies have found that the final breast volume does not appear to be strongly correlated with the dose or type of oestrogen used. What does seem to matter is avoiding very high doses in the early stages of treatment, because there is evidence from research in related conditions such as Turner syndrome that too much oestrogen too soon can actually limit ductal branching and result in development that plateaus at an earlier Tanner stage.
This is one of the reasons why good clinical practice involves starting with lower doses and gradually increasing them, mimicking as closely as possible the hormonal pattern of natural puberty. Rushing the process is counterproductive, and self-medicating with very high doses outside of medical supervision carries real risks, including the risk of limiting the very development someone is hoping to achieve.
Trans Young People and Gender-Affirming Care
For trans girls and trans young people who are assigned male at birth and are beginning gender-affirming care, there is understandable hope that early intervention will lead to more complete breast development. The picture here is genuinely complex.
Puberty-pausing medications, known as GnRH agonists, can be started at Tanner Stage 2 to prevent the progression of unwanted masculinising changes. When a trans girl then begins oestrogen, breast development proceeds in the same way as in cisgender female puberty, following the Tanner stages from Stage 2 onwards. One study observed breast development to Tanner Stage 3 after two years of hormone therapy in trans girls, which aligns with what we see in cisgender puberty over a similar timeframe.
A careful study measuring breast volume using three-dimensional scanning in trans women found that those who had begun puberty suppression early in puberty, at Tanner Stage G2 or G3, did not have significantly different breast volumes from those who had started suppression later or who had begun hormone therapy as adults. The researchers adjusted carefully for differences in body composition, and once those adjustments were made, the differences were very small. This is an important finding: it suggests that while timing of treatment matters for many other aspects of wellbeing and physical development, breast volume may be influenced by factors that remain partly independent of when hormonal treatment begins.
What we do know is that beginning gender-affirming care before irreversible masculinising changes occur has profound benefits for the mental health and wellbeing of trans young people. The evidence on this is clear and consistent.
Does Progesterone Help with Breast Shape?
Progesterone is a topic that comes up a great deal in trans healthcare communities, with many trans women reporting that adding progesterone to their hormone regimen seemed to help their breasts move from a conical shape towards a rounder, fuller appearance. This is a genuinely interesting observation, and it reflects what progesterone does biologically: in cisgender female development, progesterone is involved in the maturation and differentiation of breast tissue, which is part of the transition from the earlier conical Tanner stages to the rounder mature form.
The clinical evidence, however, is mixed. Most formal studies have not demonstrated a significant effect of progesterone on breast volume in trans women, and the Endocrine Society guidelines note that current evidence neither supports nor definitively rules out a benefit. The honest answer is that we do not yet have the high-quality data to be certain, and for many individuals the question remains open. If you are considering progesterone as part of your care, this is a conversation to have with your prescriber, weighing the potential benefits against the known risks, which include effects on mood and cardiovascular markers in some people.
Body Image, Emotional Wellbeing, and Finding Support
Whatever the physical outcome of breast development, the emotional experience of watching your body change, or not changing as quickly or fully as you had hoped, is significant and real. Trans women who are dissatisfied with their breast development have options, including surgical augmentation, which is the most commonly pursued gender-affirming surgical procedure. Around sixty percent of trans women eventually seek augmentation, and satisfaction rates are generally reported as very high.
For those who are not seeking surgery, or who are not yet at that stage, understanding what is happening and why can make a meaningful difference. Knowing that a conical shape is not a sign that something has gone wrong, but rather that development is sitting at a particular Tanner stage, can be genuinely reassuring. It does not make the dysphoria disappear, and I am not suggesting it should. What it does is give you accurate information, and accurate information is the foundation of good self-advocacy and good healthcare.
I also want to say clearly: whatever shape your breasts are, that shape is yours. Your body is doing something extraordinary in responding to hormones and creating tissue that reflects who you are. That matters, even when it does not feel like enough.
Resources
De Blok, C.J.M. et al. (2018). Breast Development in Transwomen After 1 Year of Cross-Sex Hormone Therapy: Results of a Prospective Multicenter Study. Journal of Clinical Endocrinology and Metabolism, 103(2), 532-538.
Wierckx, K., Gooren, L. and T’Sjoen, G. (2014). Clinical Review: Breast Development in Trans Women Receiving Cross-Sex Hormones. Journal of Sexual Medicine, 11(5), 1240-1247.
De Blok, C.J.M. et al. (2025). Variations in Volume: Breast Size in Trans Women in Relation to Timing of Testosterone Suppression. Journal of Clinical Endocrinology and Metabolism, 110(5).
Patel, H. et al. (2021). Chest Feminization in Male-to-Female Transgender Patients: A Review of Options. Transgender Health, 6(5), 244-255.
Hembree, W.C. et al. (2017). Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology and Metabolism, 102(11).
Marshall, W.A. and Tanner, J.M. (1969). Variations in Pattern of Pubertal Changes in Girls. Archives of Disease in Childhood, 44(235), 291-303.
If this article has been useful to you, please share it with someone who might need it. The more people understand about how bodies work and what to expect from gender-affirming care, the better equipped everyone is to have the conversations that matter.
Dr Helen Webberley | Gender Specialist and Medical Educator
www.helenwebberley.com