Heterosexuality is the null hypothesis. In other words, it's the norm, it is assumed, and it is the morally superior orientation. All moral codes that have ever existed make this determination. Furthermore, heterosexuality is in the interest of the state. Heterosexual relationships are better for the economy, and produce the next generation of citizens.
Homosexuals spend very little money on children, resulting in greater accumulations of wealth. Accumulations of wealth are good for the person, not good for the economy. Economy is money in motion. Most heterosexuals largest expense is their children, on local services such as child care.
Populations need a 2.1 birth rate for population maintenance, a higher rate for growth. Homosexuals do nothing to this. Adoption by homosexual couples could be an answer to the first point, but not this one.
Heterosexuality is the norm, and most beneficial to society.
Homosexuals should be free to be what they are, that is not in dispute, but their benefits to society are far less. And don't give me any bullshit about the arts.