I'm not saying that I'm a homosexual but those homos you referred to are also human.
And you're judging their capability because of gender. How nice.
I think that every human is a human, you are right there However I disagree with your second sentence, father( or male to be more ....) can't replace real mother (female).
Biologically yes, but it doesn't require a specific gender to show love and care for a child and stand up as their parent or guardian. And homosexuality has been in play way before this concept of making them taboo has taken place. I don't see anything wrong. Even the overly manly Spartans have same sex lovers.
But raising a child with wrong principles is harmful for our society. You can show love to a child no matter of what you are buy you can't teach or rather show important things. Either way the scale of this problem is very small so there is no need to prevent, I hope it will stay as it is.