Whether or not someone is born with a particular disposition does not mean that it is in the best interests of society to normalize or certify that disposition. Some people are born with violent tendencies or attraction to drugs or perversions or whatever. Such persons should be loved, but it is not rational to demand that a disposition at birth be automatically recognized as proper.
There are a number of reasons that are not even religious as to why it is not in the best interest of a society to normalize non-male-female “marriages.”
See
Not all marriages are created equal
Talk by Dr. Jennifer Roback Morse on why a society should not attempt to make same-gendered “marriages”
Replies to “gay marriage” arguments 1
Replies to “gay marriage” arguments 2
I’m sure there are other resources. But the reasoned mind can hopefully recognize that this largely is not an arrangement advantageous for children or a society.
And remember, to teach your own children to love, love, love - which means they would not confirm their friends in a lie, which gay “marriage” is. They would not confirm their friends in the idea that this is a matter of “equality,” which it is not. The great thing about love is that one learns to care for others ultimately beyond that other’s emotional satisfaction.