How to decide what makes something a "baby"

Echidne has a great post about the extreme right's push to get rid of the birth control pill. This urge is nothing new, of course. The pill has been a source of contention for a long time, but it was put on the back-burner while abortion rights were attacked. I guess they figure it's safe now because they have someone in the Oval Office who needs their vote so badly he would be sympathetic if they started making noises about how Jesus wants his revenge on the Jews now. But he's especially sympathetic to the anti-woman rumblings--women who are offended by that are probably going to vote for the other guy anyway.
Growing up, I heard from Bible-thumpers all the time that the pill was killing a baby, that it was evil, *snooze*. Apparently, the extremely tortured logic is that when a woman's on the pill, an occassional egg slips by, gets fertilized and doesn't implant. There's no real evidence for this, of course. And even if it does occassionally happen, it's not as common as they make it sound. They make it sound like uterine rejection of a fertilized egg is the second line of defense for a weak first line. When, of course, the supposed first line of defense is pretty much the only real thing the pill does.
Anyway, as I pointed out in the comments, the evidence is pouring in that a woman's uterus rejects many, if not most, of the eggs that get fertilized. If a fertilized egg is really a baby, then that means that a good Christian woman who uses no birth control "kills" far more babies than a woman who takes the pill until she tries to conceive, minimizing her ovulating and therefore "baby-killing" years. Clearly, the whole thing is ridiculous. If god wanted to put a soul in a fetus early, why wouldn't he wait until it implanted in the uterine wall and give it a fighting chance? If he doesn't care and lets babies die willy-nilly, why not put a soul inside every single one of a woman's half a million eggs? Or one in everyone of a man's billions and billions of sperm?
The earlier Catholic Church determined that a fetus was only ensouled during quickening, when the mother could first feel it move. Or, baring that, it was determined to be human when it first looked human, a hazy state at best. Before that, abortion was acceptable. Of course, then they also believed that men had all babies fully formed inside their testicles and that women were just potters for babies to grow in. There was alot of resistance when microscopes were discovered and therefore sperm, which looks nothing like tiny babies, were also discovered.
Now we know, of course, that a man and a woman each contribute half the DNA to the baby. And we also know that the woman contributes everything else--nutrition, hormones, antibodies, you name it. We know that what makes a fetus a "baby" is a hazy thing indeed, since there's no magical lightening bolt when the soul visibly enters the tissue blob and makes it human. So, most of us go by the same rule of thumb. It's a baby when it starts seeming baby-like.
But fundies want a fetus to be considered a human being the second a sperm wiggles its way into an egg. Why? It doesn't make a whole lot of sense, since even after this magical event most fertilized eggs are going to act like unfertilized ones and drift out. And of course, there's the whole issue of ectopic pregnancies, which are fertilized eggs that attach even, but no one would suggest that they are babies. Why pick such a strange time in the span of a pregnancy to determine is the magical ensouling moment?
Well, I have a theory. Most of the pregnancy is about the woman's body entirely, as I mentioned earlier. The only contribution the man makes is the DNA dose. Which occurs during fertilization. Which is the first, last, and only male contribution to the pregnancy itself. So why do they consider the soul to enter the egg at fertilization? Well, it's probably because that's when the sperm enters the egg. We can't pretend that sperm are babies anymore, but we can assume that they are the agent that creates souls, and no one can prove that wrong.
The birth control pill is threatening not because of any real concern for babies or marriage. (The pill has actually done alot for families, saving marriages and helping parents better distribute resources to their offspring.) But what the pill does represent is female control. A woman can take the pill and a man can't really stop her. He may not even know. It's the symbol of female unwillingness to submit to the roles as passive receptacles, thus the language about "hostile" uteruses that are seen as rejecting zygotes. It's fairly easy to see how that is symbolic of real live women refusing to be vessels for male ideas and desires.
Of course, they think it's going to be an easier sell with this symbolism than it will be. Nowadays, most men don't really have the urge to have women lay around being passive receptacles for their will or their sperm. Despite the bruised egos of the men of the extreme right, most men are relieved not to have that responsibility anymore. But it still bodes well to be careful, because the right is far from done. They're just getting re-energized.