What should parents do if they regret ever having children?

In 2008, Nebraska permitted parents to abandon children of any age without penalty. As a result, quite a few older children were abandoned before the state changed the law. That shows that some parents deeply regret ever having children, and surely many more parents have major regrets, even though they'd never abandon their children. What should prospective parents do to ensure that they'll not regret having kids? What should a parent do if he or she realizes that having kids was a mistake? Also, is it worse for a mother to abandon her children than for a father to do so, as people commonly assume?