Married people attempting to raise children with the hope that they, in turn, will be reproductively successful, have every reason to oppose the normalization of homosexual unions.
It's about grandchildren. That's what all life is about. It's not enough just to spawn -- your offspring must grow up in circumstances that will maximize their reproductive opportunities.
In an era when birth control and abortion make childbearing completely optional, the number of out-of-wedlock births shows the contempt that many women have for marriage.
Yet most of these single mothers still demand that the man they chose not to marry before having sex with him provide financial support for them and their children -- while denying the man any of the rights and protections of marriage.
Men routinely discard wives and children to follow the nearly universal male biological desire for diversity in mating. Adultery is now openly expected of men, even if faithful wives deplore it.
With "gay marriage," the last shreds of meaning will be stripped away from marriage, with homosexuals finishing what faithless, selfish heterosexuals have begun.
(the whole article is like this, this is just a sample)