Rare Case in Australia: Twins Born to the Same Mother, but from Different Biological Parents
A surrogate mother became pregnant naturally in parallel with the surrogacy process. A son and daughter were born on the same day by cesarean section. The court was required to rule on the issue of parenthood. Both families intend to raise the children in contact with each other.
A woman from Queensland, Australia, gave birth last year to twins who have different biological parents, in a case considered the first of its kind in the country and so rare that there is no reference to it in local surrogacy laws. The woman, whose identity was not published in the verdict, became pregnant naturally and unintentionally around the same time she began a surrogacy process for another couple.
Both children were born on the same day in November 2025 by cesarean section. There was no dispute regarding parenthood of the children, and during the ten months that have passed since their birth, they have been raised separately by their biological parents.
The unique situation led to a complex legal proceeding in the Children's Court in Queensland, because the state's surrogacy laws were written with the goal of preventing situations where "siblings born in the same birth" as a result of a surrogate pregnancy are separated from each other. The court ultimately determined that although the children are "pregnancy twins," they are not considered siblings born in the same birth for the purposes of surrogacy laws, and therefore it was possible to issue an order regulating the parenthood of the biological parents.
According to the verdict, the two couples involved reached an "altruistic" surrogacy agreement after meeting through mutual friends. One of the couples, identified in the verdict as BNJ and DRJ, was unable to bring a child into the world naturally, after BNJ was born without a uterus due to a medical condition.
The couple met DZ and FZ, who were already parents to five children. DZ agreed to serve as a surrogate mother, and in April 2025, an embryo was inserted into her uterus as part of in vitro fertilization. About two weeks later, an ultrasound scan showed that DZ was carrying two embryos. Subsequent tests revealed that one of the babies, a girl, is the biological daughter of BNJ and DRJ, while the second baby, a boy, is the biological son of DZ and FZ.
According to the verdict, the son "was conceived separately from the embryo insertion process and without medical assistance." It was further noted that DZ and FZ "did not intend to become pregnant at that time," but this does not detract from the fact that the child is "loved and wanted" by them.
Earlier this year, the parties hired an independent consultant, who prepared a report for the court required for the determination of BNJ and DRJ as the girl's parents. The report noted that the fact that the children were born as twins may have emotional and developmental significance for both of them over the years, even though they are growing up in two separate homes.
Both families told the consultant that they intend for the children to grow up knowing each other, and to receive an age-appropriate explanation about their place within the extended family network. It was further noted in the verdict that the parties understood that openness and honesty regarding the girl's origin and parenthood would be in her best interest over the years.
