Yes people, it's life! Let's give you that, all right? The fertilized egg is life, just as the cells on the back of the hand are life, just like amoebas are life. But the difference between fertilized eggs and amoebas is that amoebas can live independently, eat, reproduce, experience a life cycle. And the similarity between fertilized eggs and cells on the back of the hand is that they cannot do any of those things, unless they are given an assist, the latter in a petrie agar, and the former via implantation into a uterine wall, which may or may not take. Blastocysts cannot develop independently on their own.
It comes down to this:
The National Institutes of Health, American College of Obstetricians and Gynecologists, and American Medical Women's Association all hold identical definitions of pregnancy, which, in the words of the AMWA's Position Statement on Emergency Contraception,
"defin(e) pregnancy as beginning with implantation. Emergency contraceptive pills work prior to implantation and therefore are considered by these respected organizations and AMWA as a contraceptive, not as an abortifacient. Emergency contraceptive pills do not affect an established pregnancy and numerous studies of the teratologic risk of conception during regular use of oral contraceptives (including the use of older, higher-dose preparations) found no increase in risk."
Why at implantation? Well, it may be because until implantation, the fertilized egg has no chance of growing into anything at all. It will wither and die without the sustenance provided by the endometrial wall. And many billions do. Women become pregnant regularly and cluelessly, and for her entire reproductive life each woman's menstrual waste in every country on earth has been sent over and over and over again to the garbage dump, carrying the remains of her countless failed conceptions. Speaking scientifically, blastocysts are cheaper than a dime a dozen...they are a dime a trillion, and if they weren't, not enough would successfully implant to continue the race.
Fertilized eggs are not babies, and no matter how much you may want them to be, the scientists and medical experts who know more about it than you do aren't going to call them pregnancies until they implant. And until they implant, they cannot, by any medical definition, be aborted. Anti-abortion and anti-contraception groups may devoutly wish it to be otherwise, but giving Plan B and RU-486 does not cause abortion.
You don't like it? Ok, you can define pregnancy to mean conception if you must. You can even define it to mean the first time you think about having sex with someone, or better yet, you can pass a law endowing personhood on every unfertilized egg and motile sperm sloshing around a human body, but wishing doesn't make it so. It won't make a few cells the moral equivalent of a real live woman or child. It won't endow those few cells with the capacity to suffer the pain and horror of a girl who has been eviscerated by thugs, and left to incubate their seed. But it will intesify that pain, and perpetuate it, and spread it cruelly amongst the people least able to avoid it.