I have worn a bra since I was 9 years old, and womens panties virtually all the time since I was 23. I do own some mens underwear, but wear it rarely. I am much more comfortable in panties, and I wear a bra because I have natural breasts. No, I do not have any medical condition. I started wearing a bra at age 9 because the doctor told my dad I needed to wear one since I was a 36 B. I am now a natural 40 B.