That may be true statistically, however I know many people who came from two parent homes who ended up very messed up.
I know people with two legs that ended up very messed up. It's not clear they would have done better with just one leg.
Statistically, the majority of well-adjusted kids come from two-biological-parent homes. Just as you would not want the FDA to lower the standards for vaccines, medicines or inspections of the meat you ingest, you should not want society to lower its standards for what constitutes a good enough environment for children unless you really do want to destroy this country from within. Unfortunately, we are already far down that road.