I started developing female-like breasts during puberty (coincidentally, at about the same time I started femulating). When I femulated in my teen years, I would wear my mother's bras (my sister's were too small for me) and my breasts were ample enough to almost fill out her 38B cross-your-hearts.
I never went to a doctor regarding my girly breasts, so I may or may not have gynecomastia, but having seen photos of guys diagnosed with gynecomastia, I would say that my breasts are in the running.
My girly breasts caused me much consternation when I was
young. I was ashamed of my breasts and shunned activities that involved baring
them because I feared that people would ridicule me.
My fears were justified and I was ridiculed. Some of my tormentors even went so far as to suggest I should wear a bra. One college dorm mate even offered me one of the bras that his girlfriend had left behind in his dorm room. (Thanks, Jim, but I prefer a longline bra.)
My parents never mentioned my breasts, but they did buy me weights and barbells so I could work out and shed my "baby fat." I did work out and developed some muscles (mainly in my arms), but my breasts did not go away.
As a femulator, I learned to appreciate my girly breasts.
Like I wrote above, my breasts are large enough to almost fill out a 38B bra. Also, they are large enough that I can create cleavage very easily when the neckline of the apparel I am wearing calls for it.
Admittedly, my breasts are small for a woman my size, but they are real and they are mine. Recently when a female acquaintance gave me a hug, she was impressed with the size of my breasts commenting that they were "big." I was not wearing breast forms at the time.
When I first started going out en femme, I used breast forms all the time, but now I don't bother. Not only do I prefer the feel of my real breasts resting in the cups of my bra, but now I am proud that I have girly breasts and am not afraid to show them.
(By the way, the Kayser advertisement shown above is legitimate. Kayser is a brand from Australia and New Zealand and I guess their "Choose Kayser for men" ad campaign was similar to the old "Men prefer Hanes" ad campaign here in the USA.)