When Joanna Matthews hears people crooning over a baby, declaring that "he has his mother's eyes" or "she has her father's nose," she tends to cringe. Matthews, a lesbian who plans to someday start a family with her partner, knows that current fertilization capabilities allow only one of them to be a biological parent.
Artificial insemination, the use of egg donors and surrogate mothers, and even implanting an artificially inseminated egg from one partner into the womb of the other have helped fuel what is sometimes called the "gay-by boom." And yet despite these incredible scientific advances, one fundamental reproductive goal remains unattainable: children of gay and lesbian couples that reflect genetic characteristics of both partners. "We want what most people want: a mixture of our eye colors and hair colors, our personalities, and our physical features," says Matthews, who lives in Fredericksburg, Va. "But that's just not an option for us."
Not today, perhaps. But if early research under way in Chicago, New York City, Melbourne, and other sites around the world bears fruit, there may someday be "heterosexual-free" fertilization techniques that combine the chromosomes of two same-sex partners, resulting in embryos composed genetically from both men or both women.
Orly Lacham-Kaplan, a reproductive biologist at Monash University's Institute of Reproduction and Development in Melbourne, has spearheaded a study using DNA from any adult cell to fertilize a human egg. The process would work by inserting the nucleus of an adult's cell (which has 46 chromosomes) into a female egg, with its 23 chromosomes. Scientists then force the egg to begin dividing through chemical and electrical stimulation, which prompts the donor cell to eject half of its 46 chromosomes. The remaining 23 chromosomes pair up with the egg's 23 chromosomes, resulting in the formation of an embryo with half its genes coming from each parent. Lacham-Kaplan's team has performed this technique with mouse cells in lab tests, resulting in viable embryos, but has not yet implanted them into female mice.
In January scientists at the Reproductive Genetics Institute in Chicago reported that they successfully created mouse embryos using a similar method that removes half the chromosomes from the nucleus of an adult cell. The remaining half-complement of chromosomes is used to fertilize an egg. The results of early tests on human eggs are expected to be announced in April at the Fourth International Symposium on Preimplantation Genetics in Cyprus.
While this method requires at least one female partner, the reproductive conundrums faced by lesbian couples also apply to gay males, says Alan Ross, founder of the Gay Fathers Coalition International. Only one of the men in a couple can be a sperm donor, leaving his partner without genetic ties to their child. And gay men face the added burden of finding a female surrogate willing to carry the child to term and give birth.
"That brings up all kinds of legal and financial issues that must be taken care of up front, and that can be a long and difficult process," Ross says. "When you're a heterosexual, having a baby is just part of the formula. When you're a gay man, it's not so easy."
But researchers are attempting to remove some of the scientific barriers through technologies similar to those that may eventually permit lesbian couples to conceive children. Eleanor Nicoll, public affairs manager for the American Society for Reproductive Medicine, reports that scientists at the Weill Medical College of Cornell University in New York City are working on a method to replace the genetic material in a female egg cell with the nucleus of a 46-chromosome male cell. By inducing the nucleus to undergo meiosis--a process of cell division that reduces the 46 chromosomes by half--the male's DNA in the egg can then be fertilized by his partner's sperm, which also contains 23 chromosomes per cell. …