No, I'm sure that same sex couple don't affect a child's sexual preference since I think this is determined at birth by one's DNA. And in truth, loving parents are simply there to guide and teach their children… no matter the sexual orientation. There is a story about two gay white men who adopted an African American baby that was hooked on coke at birth. They loved him and nurtured him. He grew up to be a nice young man who got great grades and played sports too, a true scholar athlete. He went to West Point… which is incredibly hard to get into and graduated recently and is now serving our country. And oh, he is straight. I know "Normal" parents that couldn't do what these two did.
It does not matter what your sexual orientation is when raising a child. Raising children is not easy or for the weak as it takes a strong heart and a strong mind to raise children now. I would think that as long as the two parents are raising a child correctly then what does it matter and why would any one care what the sexual orientation of said parents are?
Because humans are nosy and many have to get in other's business and tell them how they are wrong for this, or not doing that right. More, we seem to love to inflict our concept of morality on others, whether they want it or not.
Moral issues aside, the primary item a parent has is love and wisdom.
Your personal sexuality is not just taught from the parents it is your own life experiences that forms it.
The feeling of security in a marriage and in the home is most important for a healthy child.
After all if sexuality was only from the parents no Christian home would have anything but heterosexuals in it. We all no that is not the case.
It annoys me that people use the excuse of needing one male and one female to have a proper family. What about single parents? And the other parent doesn't want anything to do with the child? Any child can be brought up in a female or male dominant family, regardless if they are gay or not. A friend of mine has a step-daughter with his husband and that relationship has been more beneficial and secure now. A family unit is what you make it, not what society perceives it to be.