It's actually like asking why men have penises. hehe. Hormones!
Toper asked me this while we were in Anawangin. It's supposed to be relaxation... away from school stuff. But that's how it's goin to be, because when "we're" out, it doesn't erase the fact that we're med students or doctors-to-be.. (posted in jeepneys: Student fare- not applicable on Sundays... mmm... we aren't students on Sundays and holidays, huh? Driver's are not drivers when not driving? Occupation defines what you do!)... and won't be asked of these questions.
My first thought was "weelll, because he's a guy, that's why" pero I thought of the exact answer pa. After 5mins,
Angel: alam ko na
Toper: alin?
Angel: kasi sa hormones, male hormones
Toper: iniisip mo pa rin hanggang ngayon???
Angel: hehehe
Weird, it's simple. What made me think too hard? I was right nonetheless.
In the prepubertal stages, endocrine glands mature and at puberty, hormones are released. Secondary sex characteristics begin to manifest. Along with the breast budding and pubic hair growth is voice change. That's why they "piyook" haha.
Testosterone during puberty causes enlargement of the larynx and thicningof th vocal cords which result in a deeper voice - Berne and Levy
Certain parts of the body are testosterone/androgen specific, meaning receptors are present in these sites so that during the release of the hormones, they bind to these receptors stimulating reactions that cause changes. =)