Did you even bother to follow the link? Here, I extracted the reference for you [1]. "Chinese and Japanese populations typically lose between 80 and 90 percent

Did you even bother to follow the link? Here, I extracted the reference for you [1]. "Chinese and Japanese populations typically lose between 80 and 90 percent of their ability to digest lactose within three to four years of weaning." (Swagerty et al, 2002) Ergo, lactose intolerance is a factor in children in some genetic groups. Your citation (sourced from the same wikipedia page) does not refute that. [1] http://en.wikipedia.org/w/index.php?title=Lactose_intolerance&oldid=236949155#Lactose_intolerance_by_group http://en.wikipedia.org/w/index.php?title=Lactose_intoleranc...