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Name: Deborah
Status: Student
Grade:  Other
Location: NY
Country: United Kingdom
Date: Summer 2009


Question:
Okay, I understand that with gestational surrogacy the sperm comes from the Father and egg from the Mother, BUT...with the surrogate, does not her blood contribute to DNA?



Replies:
The simple answer is that the DNA from a child comes only from its genetic parents, not from its surrogate.

Moreover, even with traditional surrogacy (where the surrogate/host is also the genetic mother), the DNA for the child comes from meiosis/fertilization. The mother's DNA does not interact with the fetus' DNA during pregnancy.

If you want to learn more, there is a so-called "placenta barrier" that prevents exchange of the mother's blood with the fetus' blood. Small molecules (nutrients, etc.) may pass through the placental barrier, but larger molecules (proteins) or cells cannot. DNA typically resides inside cells, which cannot pass through the barrier. Moreover, even if DNA were to pass through the barrier, human cells have many mechanisms to prevent incorporation of random DNA from their surroundings. If you do an internet search for "placental barrier" you can read much more detail about how this works.

Hope this helps,
Burr


No. Contrary to popular belief, the mothers and baby's blood don't actually mix. Whatever the baby gets from the mom has to diffuse through the umbilical cord. So the surrogates blood doesn't actually play a role.

Vanhoeck



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