Most Helpful Guy
Yeah, absolutely. I think it's mostly to do with genetics, but weight gain definitely plays a factor. I knew a girl who started college with small C's or full B's, but ended with some giant like... F or G cup boobs., and they were super perky too. She was a totally bitch, but god I loved her tits.
Most Helpful Girl
Hormones. Either food or natural. A final release of hormones causing this in the 20's is not uncommon.
Then there's the BC Pill.