Does life begin at conception, or does Judaism take a different view? At what point does life begin?
For most halachic purposes, life begins at birth - to be exact, at the emergence of either most of the head for a normal birth, or most of the body if it's a breech birth (Niddah 28a). For that reason, if a pregnancy is endangering the mother's life, an abortion may be performed (see Shalom's answer here), whereas once the head has emerged we may not do so, because that would be outright murder (Sanhedrin 72b).
Generally, though, a baby less than 30 days old is considered possibly non-viable; for that reason, if he dies (G-d forbid) during that time, his parents don't sit shiva for him (Shulchan Aruch, Yoreh De'ah 353:4).
Beginning at the time an embryo is implanted in the uterus, we have a "potential life." If a woman is pregnant at a very early stage (even between implantation and forty days), Shabbat or Yom Kippur may be broken for the needs of her pregnancy. (Now practically anything that puts the fetus at risk is putting the mother at risk too, as it's far more dangerous for the mother to birth a stillborn than a live child; but the medieval commentaries made it clear that this was even true theoretically, to allow a potential life to come to fruition.)