Some interesting speculation on why menstruation evolved in humans ties it back to the competition between women and their embryos, and the frequency of genetic abnormalities in our species. Around half of human embryos fail to implant. Naively, that’s a large fraction at a stage in the biological lifecycle that should be relatively risk free.
There have been quite a few articles in the news recently on the rejuvenation powers of young people’s blood. What’s going on is subtle and not yet well understood. Anyone injecting themselves with blackmarket GDF11… well, let’s just say that was a stupid thing anyway.