My thoughts are that even though, all our lives we have been taught that breasts are a sexual item. 16 year old boys are fascinated by them because it is "taboo" and "sexual" while yes you can get sexual pleasure/arousal from touching or fondling them, but you can also get sexual pleasure/arousal from kissing/touching/rubbi ng other "non sexual" parts of the body. what makes the built-in baby feeding system so different? is it just a social stigma, or am I missing something else?
fun little trivia:
Zoologists point out that no female mammal other than the human has breasts of comparable size, relative to the rest of the body, when not lactating and that humans are the only primate that has permanently protuberant breasts.