Monday, September 7, 2009

Homosexuality

Homosexuality has been observed throughout the animal kingdom. Everything from elephants to dolphins to birds have been observed engaging in homosexual behaviour. There is plenty of evidence for the existence of genes that predispose the carrier to homosexuality. From an obvious Darwin - pass on your genes perspective being gay (thus probably/possibly having a pair of recessive gay genes) would not seem like a winning combination for the mere passing on of one's genes. This is one of the main reason based arguments against the naturalness of homosexuality - others don't accept it because of the dogma of some old text (such as the bible).

However, homosexuality is observed throughout the animal kingdom thus is quite natural and normal.
For this practise to manifest itself throughout so many species it seems plausible that there would be an evolutionary advantage to being a carrier of a recessive gay gene while still carrying a dominant straight gene. This pool of the population is liable to have some sort of genetic advantage over people who have two straight genes in order for homosexuality to be as prevalent as it is.

A good example to explain this phenomenon: Sickle Cell Anemia: This is a recessive genetic disorder where if the child receives this recessive gene from both of their parents then their blood cells are malformed and don't work correctly and lifespan is shortened. It turns out that if you are a carrier of the recessive sickle cell gene while also having a dominant non-sickle cell gene then you are immune to contracting malaria, one of the biggest killers in sub-saharan Africa (where this sickle cell phenomena is prevalent). Being immune to contracting one of your region's deadliest diseases would make you more likely to pass on your genes by reproducing (having children).

So the big question is: what would make a person with a dominant straight gene and a recessive gay gene more likely to pass on their genes? (as an overall effect in the population)

The first possible answer that comes to mind is that for males, having both the dominant straight gene and the recessive gay gene might make them more effeminite and potentially more likely to stay and commit to the long term goal of raising offspring (this can be an involved process in many animals and potentially a multi-decade process for humans). Or another way of putting it is perhaps male heterozygotes are more likely to invest in the well being of their offspring. Have you seen the movie March of the Penguins? The movie demonstrates how a male and female penguin would typically cooperate on caring for an egg under extremely harsh antarctic conditions. It turns out that two central park male penguins not only coupled but also were given an egg that needed hatching and cooperated together to succesfully care for the egg!

So, homosexuality? Well that's as natural as Bruno:



I found this picture on the internet and thought of where I live in Toronto (this picture is from elsewhere). In Toronto the gay neighbourhood is centred on Church St.!