Fetuses develop into babies given adequate care and resources.
Let me stop you right there. A spark leads to fire, fire shoots out embers, those embers are the 'seeds' by which the fire spreads. Just because those embers aren't the manifestation of fire doesn't make them any less part of the fire. When those embers land on something combustible, they become fire, the fire they start is the same fire that birthed them.
We all know what can start one. Lightning, a match, a spark, anything hot enough. But we know where and how a fire originates. However, as far as human beings are concerned, we are the only sentient species that doesn't recognize our own offspring in the stages of prenatal development. That frankly is disturbing.
These 'fetuses' are human in origin, and are therefore human. Human in, and human out. The moment they begin developing human characteristics is the moment we stop calling the child a fetus, but a baby. When you look at a 3D ultrasound, with a 'fetus' developed enough to see limbs, fingers, toes, and facial features; you automatically recognize it as a baby, not anything else.
A fetus is no more a child than a tree is a seed.
But it doesn't make them any less of a member of their progeny, does it? A seed can spawn a tree, and we know where it comes from. The seed comes from the tree, a tree is born from a seed. The cycle of life, death, and rebirth. Hand in glove.