Testosterone makes men more aggressive, assertive, sexually active, and display riskier behaviours. Therefore, from an evolutionary perspective it is not necessarily a bad thing that this challenging hormone declines as we get older, after all, maybe nature was trying to keep us safe? No-one wants a grandfather who is trying to fight with the younger men in their tribe in an attempt to win the sexual affections of their women. Another potential evolutionary advantage to dropping our testosterone is that we are less likely to undertake risky behaviours and possibly live long enough to impart the wisdom we have gained through our previous years of survival. Of course, if we are being really true to our genetics, it is only relatively recently in human history that men have lived into their 60s and beyond, and we don’t even know if this is supposed to happen. So perhaps from a evolutionary perspective, our drop in testosterone is nothing deliberate, but just that we were never supposed to live past forty.