1: homosexuals do NOT produce offspring (with their chosen partner), so they do not in any way further whatever race they belong to on an evolutionary basis.-- i am aware lesbians can produce offpsring through artificial insemination, but that still leaves out the other half of the homosexual community. The idea of sex is to procreate, if you can't procreate with your partner, you are making a bad decision on an evolutionary basis.
Not an argument against homosexuality. Stating that people are genetically inclined to reproduce is a gross oversimplification of biology and psychology.
2: according to research by these people -- Timothy Biblarz and Judith Stacey -- children were more likely to depart from their traditional gender roles. AKA, boys were more likely to grow up to be nurturing and non-aggressive, and females were more likely to grow up the opposite. They made it clear that they believe "a difference is not necessarily a deficit" but that is only an opinion.
Not an argument against homosexuality.
kind of funny the first page of posts didn't have my first point, not that i have anything against homosexuality, i have a few homosexual friends and they're great, but these are just facts. No offspring = no evolution.
Because the first point is not an argument against homosexuality. It's not even a valid argument in the framework of evolution.
The OP asked for arguments against homosexuality.
Since arthra was pounced on, irrationally, by members of this forum for actually doing what the OP asked, and being the only able to do so, I'll repeat his debunked argument.
The Freudian argument is that homosexuality is a deviation from a naturally designed course of sexual development. The problem with that line of reasoning is that it lacked any empirical data to support it and was solely based on the opinions of Sigmund Freud. Who, let's face it, is given far more credit than he deserves in the field of psychoanalysis which walks the line between science and pseudoscience anyway. There have been other non-religious arguments based on psychology taking the same route. That, in essence, homosexuals are merely heterosexuals acting out in deviant ways.
Those are arguments against homosexuality because, like the religious arguments which call homosexuality unnatural or a choice, they all essentially state that natural states of sexuality outside of heterosexuality do not exist.
But they do. Homosexuality, bisexuality, male, female, intersex........they all exist and to date no mechanism of choice has been shown to be involved in determining any of these. Also, being a homosexual just isn't about the sex. If heterosexuality were just about sex than rape wouldn't be illegal, it would be a sport.
So there are no arguments
against homosexuality. Hell, since sexual dimorphism in humans is now known not to be an absolute "way of things" any argument against a group because they cannot sexually reproduce is not an argument against the existence or natural development of the group.
It's merely an argument that a specific group cannot sexually reproduce and nothing more.
The moment a non-religious person starts using the terms meant, genetically designed for purpose or anything similar you might as well be talking religion.