Cows aren't the same as human beings, but either way you're killing both of them. I'm just saying, if you're that concerned about killing a fetus, you should feel guilty about killing animals for food as well. See now like Lizard Dude said, I don't care who kills what.
See, the reason I say it's better to kill a baby or mentally ill patient than a normal human is that regardless of what you say, they can't appreciate their 'human life' the way a regular being can. Look at it this way: if you were forced to kill one person out of a group of three, who would you kill? A newborn baby, a 10 year old boy who's just starting to understand the world around him, or a 30 year old mother supporting her two kids? If you have any sense of moral well being, you'd kill the baby. The baby is thoughtless, mindless, it can't understand it's being killed, and it isn't missing much.
It's this same reason why I think funding research on baby diseases like SIDS is a waste of money. They should be using that money to research cures for more horrible diseases like breast cancer and such.
Point and case, in my opinion, human life should be measured on said human's ability to recognize and appreciate its own human life. Basically, you need to acknowledge your own existance to... well... exist.