Chimerism and Estates
Doreen So recently wrote about Howard W. Jones and how the developments that he made in reproductive technologies have the potential to impact estate planning and intestacy laws. An issue encountered in recent news may give rise to further uncertainty when it comes to the estates of individuals conceiving and being conceived through assisted reproductive technologies.
An article appearing in the Hamilton Spectator tells the story of how the paternity of a child conceived in vitro in Washington recently caused considerable confusion. After their baby had been born, the couple questioned whether the wrong sperm sample had been used, as the child’s blood-type was inconsistent with those of its parents. After this discrepancy came to light, the couple arranged for a DNA test to be conducted. The testing confirmed that the sperm donor and intended father was not a biological parent of the baby. Surprisingly, the results of the DNA testing revealed that the man was (biologically, at least) the baby’s uncle.
A geneticist at Stanford University investigated the situation and determined that the cause for the unplanned degree of relatedness between the mother’s husband and their child was a what is known as a chimera, rather than an error made at the fertility clinic.
Chimerism, also known as the “vanishing twin effect”, occurs when two zygotes fuse into one, which is estimated to occur in as many as one out of eight pregnancies. The fusion of two twins results in one embryo that may consist of DNA derived from both zygotes. In this specific case in Washington, some of the sperm donor father’s germline cells, being those that have the capacity to develop into eggs or sperm, were derived from his unborn fraternal twin. As a result, 90% of the man’s sperm contains his own DNA and the other 10% contains the genetic material of his “brother”, giving rise to the ability of the man to father his own genetic nephew or niece. The article reports that the man has another child, in addition to the newborn, who is, in fact, his biological child.
The incidence of chimerism, which is believed to be increasing with prospective parents more frequently obtaining assistance from fertility clinics, further complicates the issue of entitlement to a biological parent’s estate on intestacy and qualification as a member of a class identified within testamentary documents. It will be interesting to observe how the case law may develop to address these issues.
Thank you for reading and have a great weekend.