The main downside is for the children. Believe me, you would not want to be the child of such a man or such a woman.[0] This is worse than lack of iodine, lead in the pipes, or congenital deformities from pregnant drug abuse. It's a societal time-bomb.

[0]: http://www.fathers.com/statistics-and-research/the-consequen...

Some statistics:

> Children living in female headed families with no spouse present had a poverty rate of 47.6 percent, over 4 times the rate in married-couple families.

> The U.S. Department of Health and Human Services states, “Fatherless children are at a dramatically greater risk of drug and alcohol abuse.”

> Children of single-parent homes are more than twice as likely to commit suicide.

> Children age 10 to 17 living with two biological or adoptive parents were significantly less likely to experience sexual assault, child maltreatment, other types of major violence, and non-victimization type of adversity, and were less likely to witness violence in their families compared to peers living in single-parent families and stepfamilies.

The "gender roles" crowd is deeply dogmatic and misguided, and it's having incredible consequences.