For many years, psychiatrists also blamed mothers when it turned out their sons were homosexual. A handful still do. A woman who bonded too closely with her boy, combined with a father who was cold and distant, supposedly led the child to develop longings for men rather than women. After research showed that gays and lesbians came from all sorts of families and usually led normal, happy lives, mainstream psychiatry not only rejected the bad parenting theory but decided homosexuality wasn't a mental illness in the first place. Psychologists also point to attention deficit hyperactivity disorder and eating disorders as problems that in the past were pinned on parents but are now recognized, more and more, as probably biological problems.
Experts offer several explanations.
One is plain old sexism. Another is that women, then and now, carry the bulk of the responsibility for child care and subsequently the bulk of the guilt. Lastly, some say it's because the mother-child bond tends to be placed above all other bonds, since she's the one who physically birthed the child. Of course, no one would argue that mothers have no influence over their kids' development at all. We need to make more complex judgments about these things.