A very common question that people have is whether the surrogate mother shares the DNA with babe in case of gestational surrogacy .
The short answer to this question is - No!
In gestational surrogacy, the surrogate mother carries an embryo created from the eggs and sperm of the intended parents or donors. In this case, the surrogate mother is not genetically related to the baby and does not share DNA with the baby. A gestational surrogate is called the "birth mother" and the biological mother is still the woman whose egg was fertilized. The reason for this is that the genetic material of the embryo comes entirely from the egg and the sperm used to create it.
The placenta allows nutrients that the baby needs to pass from the mother to the baby. It also lets waste that the child doesn't need go back through to the mother. But the placenta doesn't let blood or other cells from the mother or child pass through. So once the embryo is implanted in the surrogate mother's uterus it develops and grows using nutrients from the mother's body, but the genetic information remains the same.
There was also an opinion connected with a phenomenon called microchimerism, where small amounts of cells from one individual are present in another individual's body. This can occur during pregnancy when some fetal cells cross the placenta and enter the mother's bloodstream. However, these cells do not integrate into the mother's tissues, and they do not affect the mother's DNA or the DNA of any future children she may have.
There were done many studies that proves no genetic connection between surrogate and baby. One study published in the Journal of Assisted Reproduction and Genetics in 2015 looked at the genetic material of 16 children born via gestational surrogacy and another study published in the Journal of Clinical Endocrinology and Metabolism in 2016 looked at the genetic material of 36 children born via gestational surrogacy, in both cases there were found no evidence of maternal DNA in any of the children, indicating that there was no transfer of genetic material from the surrogate mother to the child.