Humans lost their penile spines during millions of years of evolution.

People believed ‘humans evolved smooth penises as a result of adopting a more monogamous reproductive strategy than their early human ancestors. Those ancestors may have used penile spines to remove the sperm of competitors when they mated with females.’ But it is not the reason for losing penile spines. Researchers recently found that the chunks of DNA that had been lost from the human genome but not the chimp genome, was the reason. [Read more…]