Not great news for guys with crazy beards and great hair. Most guys who can't grow a beard wish they could. However, maybe not so much after they hear this.A new study of primates found that guys who can easily grow a big beard might have smaller testes.Researchers in Switzerland looked at various sexual traits in 100 different primate species, including humans. What they found was a trade-off. See, male primates with big beards and lots of hair tend to have less going on downstairs. That doesn't necessarily mean they get less action though. Harrier males tend to be perceived as more masculine by females, so they attract more mates and tend to get more chances to produce offspring.