A body having a pulse is not what matters.

Cancer cells are also genetically human and also alive.

If it isn't sentient, its life is irrelevant.

If it isn't sapient, furthermore, it does not matter as much as the sapients its existence imminently effects.

A fetus is neither.

A baby, once capable of surviving without parasitically siphoning off the body of a host through a direct persistent flesh attachment, is either sentient or shall imminently be if left to its own devices

(Whereas a fetus without a host, when left to its own devices, shall imminently be dead and never to attain sentience nor sapience)

Those are where the lines are drawn.