New Genetic Associations For Testosterone Levels in Men

A study in male twins showed that genetics accounts for up to 65% of the variation in blood testosterone between individuals. However, up until this month, very little was known about the genetic factors responsible for this variation.
Read more:
http://spittoon.23andme.com/2011/10/24/snpwatch-new-genetic-associations-for-testosterone-levels-in-men/