It also begs the question of nature vs. nurture. If researchers won't take this seriously, then nobody should take their findings seriously. It's almost impossible to untangle, "single-fatherhood leads to bad outcomes because kids need a father figure in the house" from, "single-fatherhood leads to worse outcomes because the type of person who would abandon their children is likely more impulsive and less conscientious than average and those traits are heritable."