Before we begin, we must agree on a premise, without which the following argument would have no basis.
: To murder or kill an infant is immoral.
: Despite the fact that an infant lacks consciousness in the first few months of its life, it is immoral to murder or kill an infant. As a zygote or fetus possesses all forty six chromosomes which are present in a fully developed Human, they are both Human lifeforms - despite a lack of consciousness, just as a newborn is a Human life-form regardless of whether it has reached the age at which it forms a consciousness or not. Hence, to abort a zygote or fetus is tantamount to murdering or killing a newborn which has yet to form a consciousness. So, as murdering or killing a newborn is immoral, so is aborting a zygote or fetus.
: Abortion is immoral.