At the risk of starting a semi-serious conversation here, this is my position:
Up until the birth of my first child, my life and body was mine to f@#k up as I liked. I'm ultra-libertarian - what you choose to do that doesn't affect me or my family is fine and legal with me. BUT, IMHO - as soon as I created another life dependent on me, it is my duty to that child to cut that sh1t out. Now I know there are LOT'S of people who would disagree, but whatever...