Is this wrong for a mother to say to her child?

I was sitting in Benihana and the other family that was at our table was talking amongst themselves. The mom was pregnant and talking about how long it took her to conceive her child. Her other kid (probably five or six) said "how long did it take you to make me mommy?" And the woman goes "you were a mistake." Is this wrong? I wanted to say something. That poor kid's face fell.

Vote below to see results!