Hmmmm... well I think the word "regret" is quite provocative in this context.
Most people won't have a child and wish they'd never been born 
But, as with anything worthwhile there are hard times. And depending on which time / day you ask me I may miss my old child free days and feel wistful and trapped by parenthood.
But I love my kids more than I thought I would ever love anyone. They make me laugh, cry, smile, dance, shout, care, proud, cringe, content, frustrated, happy, sad, tired, amazed.... (you get the picture)
Similarly I may want to whack DH over the head with a frying pan and wish I didn't have to live with a messy MAN all the flipping time - then we will have a lovely time & I think "that's why I married you!"
Life's all peaks & troughs really from my point of view 