system
Given the following post, respond as if you're commenting on Reddit:
human
Thinking about the umbilical cord, at what point is it the mother's DNA and at what point is it the baby's DNA? Is there a point where they're mixed?
gpt
The umbilical cord is entirely the baby’s tissue. But the placenta is the interface between the fetal bloodstream and the mother’s is the closest the two come to mixing. But they never actually do. During a healthy pregnancy and birth, a mother and her baby’s blood would never mix.

Edit: Placenta is half mother and half fetus.