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An embryo that died in the womb was able to become a father after many years
Last reviewed: 02.07.2025
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In the United States, specialists have completely accidentally recorded a unique case of fertilization, when the father of a completely healthy baby was an embryo that died in the early stages of pregnancy in the womb of the mother.
As it turned out, the child's father (whose name is not disclosed for obvious reasons) had a twin brother. As a result of a rare genetic phenomenon - human tetragament chimerism, when embryonic cells merge in the early stages of pregnancy, and the surviving embryo receives two sets of DNA - its own and that of its deceased twin.
According to American experts, this case was the first in history; scientists admit that such fertilization could have happened earlier, but it was the American couple who became the first known in scientific circles.
Chimerism (a set of two DNAs in one person) is usually detected by chance, and scientists have not yet determined the frequency of occurrence of this phenomenon.
Last year, a Washington, D.C., couple sought help from geneticists at Stanford University. Dr. Barry Starr found out that the couple had a baby boy whose blood type did not match either of his parents, which usually means that the child is not biological. Since the conception occurred through IVF at a well-known clinic, and not naturally, the young parents suspected that the clinic staff had mistakenly used someone else's biological material during the conception procedure.
Stanford University specialists conducted a DNA test and stated that the biological father of the newborn was not the husband at all. But the staff of the reproductive medicine clinic were sure that there could not have been an error during fertilization and further research revealed an unusual fact about the baby's origin.
After a detailed genetic test, which also included an analysis of the genes of relatives, it was established that the husband was the uncle of the newborn, and the child had only 10% of his genes. This statement by scientists caused misunderstanding in the family, since the husband had no brothers. Further research showed that the man was actually a chimera, i.e. he had two different sets of genes.
As a result, scientists accidentally discovered a unique case in which a dead embryo was able to become the father of a healthy baby.
There are officially known about 40 cases of chimerism among people. Several cases of this genetic phenomenon were accidentally discovered during IVF. For example, German specialists described a patient who had both a male and a female chromosome set. Also, one case of chimerism was discovered in Boston, when a woman needed a kidney transplant, but the woman's sons who volunteered to be donors turned out not to be her relatives at all.
In addition to genetic chimerism, there is also blood chimerism (when a person has two blood types at the same time) and biological chimerism (when a person has two skin colors at the same time - pigmentation occurs as a mosaic, usually this phenomenon is observed during incest between two races).