If you are against gay marriage, explain why without mentioning religion

[Mnementh]

Michael-5 said:

Tom3k said:

 

However, why would anyone not look at homosexuality as a disorder similar to schizophrenea or autism? Just because the consequences aren't as extreme, doesnt mean that they are not disorders. They do affect an individuals normal life. Normal people have sex with the opposite gender because that's what were genetically programed to do. Evolution did not evolve homosexuality into our code, if you took any courses in bio, you would have learned that all evolutions only occur because of a corresponding increase in fitness. If there is a decrease in fitness, then those genes would have been weeded out long long ago.

If homosexuality were a gene, it would get weeded out because a higher % of homosexuals (or bisexuals) would not reproduce then a similar population of heterosexuals. This is the same logic as how pest resistance work (where eventually all pests become resistant because they are the only ones who have reproduced).

You are wrong. If you think about homosexuality as a gene you think homosexuals do have the gene and heterosexuals have not. But everyone could have the "homosexuality"-gene, but it is not expressed in every individual. Or there is a gene or combination of it for heterosexuality and if something is missing the individual is becoming homosexual.

Also you're wrong about the evolutionary aspect of it. Personal fitness is not the way to look at it. Yes, from the standpoint of personal fitness, the homosexual individual has a lower probability of reproduction. But personal fitness is near to no driving force in evolution. Individuals are killed by bad luck in nature. Based on personal fitness, altruism wouldn't be develop in evolution. The altruistic individual is at disadvantage. But the image changes if we look at a population. A population with altruistic individuals is in many situations stronger than one of egoists. That's why altruism is for many social animals something that develops in evolution. In the same way homosexuality of some individuals in a population could increase the fitness of this population. There are a lot of theories for this.

One thing is clear: as we discovered homosexual behaviour in many animals, a random mutation that is a disadvantage in evolution is highly unlikely. It would have removed from the population and it is highly unlikely that another random mutation has a similar effect. And in this case the mutation must have happened hundreds of times. So homosexuality is either an advantage in evolution or not inheritable. In the second case we need a good explanation, why it happens so often (relatively) in humans and animals.