Surrogate Mothers Blood
Country: United Kingdom
Date: Summer 2009
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?
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,
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.
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Update: June 2012