A baby, born from two dads? It’s possible, says a leading British scientist.
Calum MacKellar, a lecturer in bioethics and biochemistry at Edinburgh University in Scotland said today that, borrowing from techniques used to clone Dolly the sheep, male couples could someday conceive their own children.
Creating a ‘Male Egg’
The technique, which scientists agree still lies far in the future, would use the egg of a woman. Genetic material inside the woman’s egg would be removed and replaced by the DNA of one of the men. That “male egg” would then be fertilized by the sperm of the other man and a surrogate mother would carry the child to term.
MacKellar admits the concept will take at least “a few years” before it’s possible, but he added that scientists had tried the technique with mice and were working on developing it. Others in the field, however, argue the technique is many more than a few years away.
Maxwell Mehlman, a professor of Biomedical Ethics at Case Western Reserve University School of Medicine, points out the creators of Dolly the cloned sheep made 227 attempts to fuse the new nucleus into the enucleated egg cell and only 29 produced a viable embryo. Then, of the 29 manufactured embryos implanted into sheep wombs, only one developed into a healthy sheep. Furthermore, the health of Dolly has also been called into question in recent years as the sheep ages.
“A strong argument could be made that the risk of failure, and worse, of producing fetal or short-lived neonatal ‘monsters,’ is too great to justify human experiments in the near future,” says Mehlman.
Avoiding Clashing Sperm
Richard Paulson, chief of the division of reproductive endocrinology and infertility at the University of Southern California, already foresees one potential problem. He points out that if chromosomes from a man’s sperm were used to form the male egg, it might clash with the fertilizing sperm of the second man. That’s because both sperm cells would contain so-called centrosomes — an organelle, present only in male sperm that directs embryonic division.
“A smarter way to do it would be to take a regular somatic cell, not a sperm cell, from one man and then fertilize that with the other’s sperm,” he says.
The procedure could also lead to genetically-linked diseases. Sherman Silber, director of the Infertility Center of Saint Louis, says scientists are tracing a number of genetic syndromes linked to a phenomenon called imprinting. Imprinting occurs when a child inherits genetic material for certain chromosomes from just one parent.
This scenario is avoided in cloning, he explains, since cloning prompts an adult cell, which is complete with genes from both a mother and father, to develop into an embryo. With the male-male fertilization concept, male sperm would fertilize an egg with male genetic material.
“The condition leads to genetic diseases with terrible effects, including severe mental retardation,” Silber says. “So consider if it weren’t just one chromosomes but all chromosomes that had inherited single sex material, then you’d really have a mess.”
Still, Silber adds that in recent years, he has “learned to never say never.”
“We’re learning how plastic biology is and I’m sure it can eventually be done,” he says.
Single Idea Raises Two Debates
Of course the proposal also raises many ethical issues, including the morality of tinkering with human reproduction and human genetic material, that were first raised when cloning made its debut with Dolly the sheep in 1996. The procedure could also invite a whole other set of social issues since it would involve gay men.
The idea of single sex parenthood is constantly being addressed today since there are about 2 million gay and lesbian couples in the United States who are raising children, and lesbians commonly use artificial insemination or in vitro fertilization to conceive children. A 1994 study, published in the journal Human Reproduction, found that children of single and lesbian mothers were not harmed by their atypical upbringings. But many people still question the ability of gay parents to raise children and claim studies supporting the idea are flawed.
Paul Allen, an associate professor of medical ethics, law and humanities at the University of Florida College of Medicine, says it’s important that debates over reproductive technologies and gay parenting are addressed separately.
“It’s got all the elements for a lot of emotion and controversy,” he says. “But I think to be fair to both issues, they have to be distinguished.”
Robin Kane, a spokeswoman for Family Pride, a San Diego-based coalition that supports gay parents, adds that her group is too focused on current real issues for gay parents, such as ensuring legal parental rights for gay people, to address theoretical proposals that may lie in the future.
“Our reality is gay biological fathers are still getting their kids taken away from them in custody battles,” Kane says. “That’s where we’re putting our energy now.”
The Associated Press contributed to this report.