In the 90s, a Missouri Presiding Judge wrote Dear Abby about the 60% rate of mothers accusing fathers of sexual abuse when there's a custody challenge.
Only 2% (!!!) of the claims were valid, but these claims can get expensive and some times go too far, with an innocent father ending up in jail.
In 1995, a 12 year old Texas girl was trying to clear her father's name when she learned he had killed himself in prison. She then killed herself. The mother had forced her five years previous to accuse him of molesting her, even though it was false.