Does the mother build the baby once it's out of the womb? It still requires nourishment, and historically that would be in the form of breast milk for many months. The baby continues to grow and develop outside the womb and doesn't reach maturity for decades, at what point is it being built by itself and not by something else?

The mother feeds the fetus through the placenta, a parasitic organism, same as she feeds the baby once it's born, same as the child feeds itself into adolescence and adulthood. She doesn't build it.