Digestive problems with milk are common in some adult populations. However, some people have the ability to consume milk into adulthood, even though adults consumed no milk throughout most of human evolution.
Please read:
1) Unkindest cup
3) Eisenstein
4) Tishkoff
Altitude imposes a unique set of physiologic challenges as well to the human body, with implications for survival and reproduction.
not related to the current topic in class, but I thought it was an interesting article and question.
http://scienceline.org/2012/06/the-epigenetic-jury-is-still-out-on-c-sections/