Ladies and Fellas Needed!!!!!

ok. i am new at this but there is somethin on my mind. i was watchin this show about gays/lesbians. one lesbian couple wanted to have kids. of course she would have to pick a sperm donor, but they didn't want thet donor in the child's life. is it wrong to be a donor? i mean, you have bought another life into this world and it is part of you too. so technically seaking, wouldn't that be like selling your child? another question is in school and in the media is a perfect family of a mother, a father, a sister, and a brother. that child will grow up learning and getting aquainted with the fact that it has 2 mothers. but the child will eventually figure out that it takes a daddy to make a baby. how will a mother explain this? wat would she tell her child? not trying to go against the whole rainbow thing but how would they handle the situations?