This, I believe, will generally prove to be an oxymoron.
how? committed and homosexual unions? or committed homosexual and unions? i take it you mean the first...
You are referring to a serious difficulty in front of anyone researching this. The phenomenon of committed homosexual unions has to be studied because this is what the proponents of gay "marriage" say should exist in law. Surely we all recognize that marriages are not terribly committed either: we have adultery and divorce fairly common. So the standard has to be "homosexual unions nearly as committed to fidelity and perpetuity as marriages are".
If we simply postulate "committed homosexual unions" are not possible even by that standard, we cannot make any intelligent statement about the children that might be raised in this environment. So the researcher has to take this approach: given that "committed homosexual unions" are not an observable reality at least because where they exist in law, they are rare, and where they do not exist in law they have an extra hurdle on their way to become committed, -- what can we observe about, simply, people with homosexual behavior who are responsible for raising children? It turns out that homosexuals are a negative factor in the lives of the offspring, comparable to divorce and step parenting. So therefore, even if the homosexuals clear every legal hurdle, and form committed unions comparable in fidelity levels to the heterosexual couples, they will continue to be a negative factor simply because they are homosexual. That is, I think, the salient conclusion one draws from the article.