It's an admission that may be the ultimate parenting taboo: People who regret having children.

Parents are sharing their deepest thoughts about parenthood on a range of public forums from Facebook to Reddit. 

The sites have messages from mothers who became parents just to please their family, fathers who feel envy when they look at their childless friends, and parents who wish they could just go back in time and make another choice.

One expert says we need to offer a "compassionate" ear to parents who are sharing feelings that are difficult to discuss.