oopsbaby

A child with a highly disfunctional upbringing that is often the cause of later social, emotional, and/or professional failures.

"Poor Logan couldn't help flipping out at that customers - he was an oopsbaby, and she reminded him of his awful, awful mother. "

Danielle's family had no idea what they'd do when her oopsbaby came along; they were having trouble supporting themselves as it was.