I don't understand the statement that "the egg donor does not pass on any genetic material." True, the nuclear DNA would not be passed on from the egg donor, but the baby's mitocondrial DNA (mDNA)would be entirely contributed by the egg donor. Furthermore, if the baby is female, that mDNA and only that mDNA would be passed to her offspring.
There are not many genes in the mitocondria, only 37, but they are important, partly determining a person's rate of aging, propensity toward heart disease and other medical conditions, and his or her general vitality. Therefore, the selection of an egg donor should not be considered a small matter.
Fertility drugs have offered older women a better chance of bearing children, but new advances may leave the possibility that a newborn baby could have three biological parents.
Until now, in vitro fertilization has given renewed hope to older women wanting to have children. But babies born to older women suffer a disproportionately high rate of birth defects and genetic disease.
That’s because degradation of the area of the region of the egg around the nucleus could adversely affect the babies of older mothers.
Japanese researchers have set out to fix that problem by implanting the nucleus of an older woman’s egg into the egg cell of a younger donor. That means the baby has a better chance of being born without defects.
Except now that baby technically has three biological parents: Dad, Mom and Mom’s egg cell donor.
It’s not the first time scientists have confronted the problem. In February of last year, British scientists created embryos made from the DNA of one mother and the mitochondrial DNA of another. The embryos never matured, but researchers in Oregon managed to develop mature monkeys using the technique.
The Japanese eggs have not matured so far, but 31 of the eggs were fertilized to prove the concept.
The term “three biological parents” is somewhat of a misnomer, however, since the egg donor does not pass on any genetic material. But it raises a new legal issue to be addressed.
