同性愛、両性愛も自然

Homosexuality and bisexuality commonplace in thousands of animal species and may play key role in evolution, research finds Same-sex behaviours can be advantageous from a natural selection perspective as individuals 'more likely to mate with more partners', scientists say Harry Cockburn 2 days ago 33 comments

　動物にも同性愛者がいるわけで、その意味で同性愛、両性愛は自然なのだが、なぜ、そうなのかについてうまい説明がなかった、と。

 They argue a combination of same-sex sexual behaviours (SSBs) and different-sex sexual behaviours (DSBs) is an original condition for all sexually producing animals — and that these tendencies likely evolved in the earliest forms of sexual behaviour.

The authors suggest not only that same-sex behaviours are often “not costly”, but can in fact be advantageous from a natural selection perspective because individuals are more likely to mate with more partners.

Many species aren’t inherently monogamous but instead try to mate with more than one individual. In many species it can be difficult for individuals to even discern between different sexes.  

　異性愛が正常、普通、という前提が間違っているのではないか、と。一夫一婦ではなく、複数の個体と交尾する動物種は多いし、同性か異性か区別つかない場合もある。異性愛、同性愛の区別なくより多くの個体と交尾したほうが、自然淘汰の面で有利で、そちらのほうがむしろ原初的な状態だったのではないか、と。