So, I have a bone to pick (so to speak).
There's this idea running around that in trans women, breast growth stops around the 2 year mark. That idea is completely incorrect.
(Note that, for the sake of simplicity, I'm going to refer to "cis girls" and "cis women" a lot, but what I really mean is "anyone who went through an estrogen-primary puberty and had roughly normal breast development" which is a lot to type out every time. And by "trans women" what I mean is "anyone who went through a testosterone-primary puberty without notable breast growth, and starts taking exogenous estrogen which stimulates breast growth." Also too much to type out every time.)
This completely incorrect idea is based (as far as I can tell) on a study by Meyer et al. in 1986:
https://pubmed.ncbi.nlm.nih.gov/3013122/
It says, right there in the abstract:
Maximum breast growth required 2 years of [hormone] therapy.
I'm not going to pay $40 to read someone's out-of-date opinions on a cohort of 60 "transsexuals" and equine estrogen (aka premarin, aka the stuff we stopped using years ago), so I won't try to prove to you that this is true, but I have heard and fully believe that this study was funded for, yes, two years' time. That is, they ran the study for two years, then stopped.
Then they published their results.
And, sure enough, they saw the maximum breast growth after 2 years. Because that was the end of their study.
Now, unfortunately, a bunch of doctors who have "done their research" on trans medicine think that breast growth "plateaus" at 2 years (it says that in the study, too). They tell their transfemme patients this, resulting in a panicked frenzy when, at 2 years, said misinformed patient is freaking out over having barely any breast growth, much less what they were hoping for.
If you look up Puberty on Wikipedia, it includes this sentence:
On average, females begin puberty at age 10½ and complete puberty at ages 15–17
Now, I kinda hate math in this sort of message, but I'm gonna hit you with a bit of math here.
15 - 10.5 = 4.5
17 - 10.5 = 6.5
That is, on average, Wikipedia's authors think puberty lasts at least 4.5 years in cis girls, and can, again on average, last 6.5 years. There's no mention of outliers, but the phrase "on average" should tell you a lot (no one is actually average).
Now, let us turn our sights on the Wikipedia article titled Breast Development. It has this gem for us:
[Breast development] occurs across several phases, including prenatal development, puberty, and pregnancy. At menopause, breast development ceases and the breasts atrophy.
(Emphasis mine)
Hmm, how long is it between the onset of puberty and the start of menopause for most women? What's that, typically 35-45 years? Thanks, Wikipedia article on Menopause!
Now, obviously trans women aren't going around getting pregnant (if you are, let a girl know, I know a couple thousand trans women whose attention just got riveted). So that's not a useful factor for us.
But, like, let's look at the numbers again.
Onset of puberty is around 10 1/2 years of age in cis girls. Puberty is considered "done" around 16 years, roughly. Pregnancy changes things, typically between 18 and 30, for most people who get pregnant (I'm guessing, don't @ me). Menopause typically starts in the 45 to 55 range. During that entire time, breast development is happening.
If you compare cis women who are 16, and those who are, let's say, 22, you will typically see substantial differences in their bodies, without factoring pregnancy in. The colloquial term is "filling out." Their bodies change, and one of the things that fills out is typically their breasts.
But wait, I hear you shouting loudly at your computer monitor, 22 years old? That's [I count on my fingers] almost 12 years! Yes, that's right.
12 or so years of development gives cis women adult looking breasts.
Gee, I wonder if trans women, who are undergoing exactly the same puberty process as cis women, just later in life, might have a similar timing?
Like, I don't know how else to say it, my lovely transfemmes. At 2 years, your breast development is just getting started. Don't let Meyer et al, from 1986 -- under-funded science from fully forty years ago -- tell you how your body works. Don't let under-informed doctors tell you how your body works.
Yeah, 10-12 years is a long time. Even four and a half years seems pretty long. Of course, you can get surgical augmentation any time you like, it's your body, that's the whole point. Wear the push-up bra. Use those cutlets (silicone breast forms, if you don't already know the term). Cis women certainly do. You should too, if you want to.
But it's going to take a while for your breasts to fully develop, and you might be really happy with the result, if you can be patient and run the marathon without trying to sprint through it. My main point is, don't panic about some mythical yet oft-repeated 2 year number. It's absolute garbage.
