If you read carefully, you'll see that the "impacts" they mention are sexual ones. (Perhaps Ms. Charen is the guilty party here....) If one is a proponent of sexual license, there would be no intrinsic problem with girls with lesbian mothers having "more sexual partners" than girls raised in normal families.
IMO what's really going on here is a misapprehension of the real issue. The basic problem is not homosexuality per se, but a cultural perception that sex is the most important consideration. Just look at how many "Big Issues" in the public eye have to do with sex (of various sorts). It's sick.
That's a great point. For me I think the most basic problem is selfishness with sex being an underlying factor. As I see it, selfishness is the root cause with adultery, divorce, abortion, homosexuality, etc as results of the basic problem or problem symptoms.