It is a sad time we live in when this needs to be pointed out. There is an excellent blog post by Dr. Tracye Hansen that highlights children's need for male and female parents. Here are a couple of quotes:
Men and women bring diversity to parenting; each makes unique contributions to the rearing of children that can’t be replicated by the other. Mothers and fathers simply are not interchangeable. Two women can both be good mothers, but neither can be a good father.
A father teaches a boy how to properly channel his aggressive and sexual drives. A mother can’t show a son how to control his impulses because she’s not a man and doesn’t have the same urges as one. A father also commands a form of respect from a boy that a mother doesn’t––a respect more likely to keep the boy in line. And those are the two primary reasons why boys without fathers are more likely to become delinquent and end up incarcerated.
Father-need is also built into the psyche of girls. There are times in a girl’s life when only a father will do. For instance, a father offers a daughter a safe, non-sexual place to experience her first male-female relationship and have her femininity affirmed. When a girl doesn’t have a father to fill that role she’s more likely to become promiscuous in a misguided attempt to satisfy her inborn hunger for male attention and validation.