Sun-Tzu makes a well argued point. (wow, tactical genius, author of the seminal work on large campaigns
and former medic? Godhead awaits

)
I just feel that semantic arguments about when foetuses become "people" or not are debates about angels on the heads of pins.
To me, the point is this: Respect for life evolves from making responsible decisions about other people. If the responsible decision is to abort, so be it. If not, don't.
But let's not pussy-foot, it amounts to taking actions to end a potential person. However, so is contraception.
I prefer to think that people should be
free to make the appropriate decision.
Incidentally, you
could also not have sex.
Call me crazy, but... well, it's the only way to avoid the matter...