Now, we need to be careful of justifying anything — heterosexuality, homosexuality, rigid gender binaries, trans identities — through simple appeals to what is ‘natural’ (i.e. found in our species’ past or in other species). There’s great value in observations from anthropology and ethology, but they need to be contextualised rather than used to fuel emotional appeals. Remember that our environment — in the evolutionary sense of ‘the conditions we’re adapted/adapting to’ rather than the simple sense of ‘the natural world around us’ — is now radically different from anything any species or culture has faced before. And it’s only going to get more different. The past will always be valuable, but it’s fast becoming hard to simplistically rely on as a guide to the world we’re living in. What is ‘natural’ in the past isn’t necessarily adaptive in the present or future.