How are gays adopting orphans selfish? They are providing a home to a child/children who otherwise wouldn't have one.
They are being selfish because they are exposing a child to an unnatural environment. Regardless of how tolerant the world becomes, the vast majority of people would be heterosexual in order to preserve the human species.
The normal convention is to grow up in a house with a mother and a father (or a single parent) instead of growing up with two mothers or two fathers. That kid will go to school and see his friends with a mother and father, and he/she will come home and wonder why things are different in his/her household.
What if that kid grows up to be heterosexual and disagrees with his parents orientation or what if he ends up in depression because he gets bullied over it or cannot cope with his parents’ sexuality.
In addition, millions of straight couples want to adopt orphan babies as well. By choosing to adopt a baby, a gay couple is potentially depriving that baby the chance of being picked up a straight couple and grow up in a normal household.
The act of adoption - whether by gay or straight couples - usually involves selfishness as well. It is rare for couples to set random babies. These usually have a preference in terms of skin color and gender. Furthermore, people often prefer babies of certain ethnicities if the information is available.
So a couple who chooses to adopt a light-skinned Pashtun boy is ignoring a dark-skinned Punjabi girl for no fault of her’s. Is this a selfish decision on the part of the couple? Of course, because they are depriving other children a life of comfort because of their selfish choices.
If we examine our actions, you will find that all of us act selfishly more often than not. There is an element of selfishness in pretty much everything we do. In fact, I cannot really think of a truly selfless act.
Hence, I don’t think it is appropriate to condemn cousin marriages because of the perceived selfishness involved.