Surrogate mothers and DNA Test

As was mentioned in the previous blog, there are some couples who have a hard time conceiving and becoming parents and have turned to assisted fertilisation techniques to achieve this goal. This could be mainly due to some types of illnesses or infertility issues, but it has also become an option for same sex couples or single individuals who want to become parents themselves.


One of the possibilities of becoming parents is by surrogacy, where an unrelated woman bears the child of the couple or individual throughout the pregnancy. This can be done in two ways, in a traditional surrogacy where the surrogate mother uses one of her eggs to be fertilised with the father’s or a donor’s sperm. The sperm can be inserted by intrauterine insemination, where sperm is deposited directly into the uterus of the mother.

The other way is by gestational carrier, where the surrogate mother carriers a fertilised egg which does not come from her. The egg or sperm can be donated by either the couple themselves or if not possible, by a donor. The egg is fertilised using in-vitro fertilisation, fertilisation in the lab by a professional. The fertilised egg is then deposited in the surrogate’s uterus where it will continue to grow until the time of birth.

Same as with other assisted reproduction techniques there is also the chance of having more than one pregnancy at the same time, for example having twins or triplets. There is no sure way to prevent this, but regular screenings will allow you to know beforehand and leave you ample time to be prepared.




Using a gestational carrier may have less complications in the long run as it is possible that a traditional surrogacy may create legal and emotional repercussions for the ones involved. As technically the traditional surrogate is donating one of her eggs, therefore she is one of the biological parents. There may be contracts drawn up before the agreement to the surrogacy detailing the custody of the child and how things will proceed after the birth. The parents may need to go through official adoption procedures to become legal guardians of the baby.


This will be where a DNA test will be useful. Let’s say the couple decided to have a gestational carrier carry their child and they used their own egg and sperm to create the embryo. The embryo will have the DNA of the donated samples, but will grow up in another carrier. The couple can carry out a paternity or a maternity DNA test to prove that the baby is biologically theirs.

If the carrier is a traditional surrogate and the sperm was donated by the father, a paternity DNA test can be used to prove that the father has a biological link to the child. The partner of the father may need to legally adopt the child to also have legal guardianship.


Will the baby carry DNA from the surrogate mother? If it is a traditional surrogacy, the baby will carry 50% of its genetic makeup, so yes they will be related. If by gestational carrier, the only way that the baby and the carrier will be connected is by the placenta which carries perhaps only a few cells from the carrier to the baby and vice versa. The amount of swapped cells will be so little that it will be inconsequential to the baby’s growth and therefore will not show up on a DNA test either. This baby will be made only from the donors’ DNA.