Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Surrogate Mothers Blood
Name: Deborah
Status: Student
Grade:  Other
Location: NY
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.


Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory