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Mama’s sperm, Daddy’s eggs

Could stem cell research lead to same-sex progeny?

In recent years, scientists have made multiple breakthroughs in reproductive technologies — technologies that could someday help same-sex couples have children genetically related to both parents.

In July the scientific journal Developmental Cell published a paper detailing an experiment in which artificial sperm was produced from embryonic mouse tissue. That sperm was then used to fertilize mouse eggs, resulting in seven baby mice, six of which survived to be adults. The study, conducted at the Georg-August University in Germany, was touted by the mainstream media as a new hope for male-female couples having trouble conceiving. Predictably, no mention was made of potential homo applications.

As a science journalist, I regularly powwow with scientists. Without fail, they’ve always been eager to get the word out about what they do. But when I began to ask how stem cell technology, like that used in the aforementioned experiment, could help queer couples have kids, suddenly no one would talk to me. Scientists who were initially psyched quickly turned cold. Others simply ignored my messages altogether. I was faced with the sinking feeling that, for the first time, I might be watching discrimination in action.

I can imagine why scientists under the current US regime might be wary of guilt by gay association. But even Canadian scientists were reluctant to comment, leaving me with a new question: why is this such an untouchable subject? The reason, so far as this humble journalist can tell, lies in the intersection of a controversial technology and discomfort with possible queer applications.

Speaking to researcher after researcher, it became apparent that the science involved is so new that the few scientists who feel qualified to speculate are either too busy or too scared to do so. After all, the process combines cloning, something akin to abortion and same-sex parenting in one messy package and that’s one hot political potato.

To produce a child with two biological parents requires two sets of DNA, one in the form of an egg and one in the form of sperm. So how do you get there when you’re starting with two eggs or two sets of sperm?

To create either eggs from a man or sperm from a woman, scientists start with a donated egg. The genetic material inside the donated egg is then scraped out and replaced with the new DNA. As soon as the DNA is transferred, the egg begins to rapidly divide, becoming an embryo in a matter of minutes. Scientists call this somatic cell nuclear transfer, otherwise known as cloning.

Human cloning has been outlawed by the United Nations on ethical grounds, and while Canada enforces this ruling by implementing laws prohibiting the practice, other countries including South Korea and the UK have been flouting international law for years in order to conduct what many consider to be crucial medical research. (In addition to the reproductive technology possibilities this research also offers the hope of stem cell-based cures to diseases such as diabetes, Alzheimer’s and Parkinson’s.)

Supposing this technology does provide the prospect of progeny by same-sex parents, a number of scientific hurdles stand in the way. To begin with, all experiments to date have been conducted using mice, and it’s unknown how well these processes would work with humans.

Secondly, although eggs have been created using both male and female DNA, as yet there’s been no sperm successfully created from female DNA. In 2003 researcher Hans Scholer and his team at the University Of Pennsylvania created eggs using both male and female mouse DNA. The sperm created last June by Karim Nayernia and colleagues in Göttingen, Germany used only male mouse DNA. Lesbians may be out of luck.

While these are very real obstacles, the conundrum of imprinting — the pattern of suppressed and triggered genes we inherit from each of our parents — poses a much more prickly problem. A fetus with two maternal or paternal sets of genes will have twice as many copies of some genes, and no copies of other genes. This can cause serious problems, leading to a variety of syndromes and even correlating with a large percentage of breast and ovarian cancer cases. Scientists have no idea if imprinting is determined by the source — an egg versus sperm — or by the source of the DNA — a genetic man versus a genetic woman. If imprinting is determined by the DNA, then we have a problem — one that scientists have no idea how to overcome.

Although imprinting is the unknown variable in this equation, there are other problems that could crop up. For instance, in the recent German mouse experiment, the sperm created from embryonic stem cells was used to fertilize a female mouse, and seven baby mice were born. One died before reaching adulthood; the rest were plagued with health problems, such as difficulty breathing, and showed abnormal growth patterns.

With breakthroughs coming hard and fast it may just be a matter of time before reproductive technologies are ready for human applications. But for same-sex couples dreaming of a bouncing baby with daddy’s eyes and papa’s smarts, time is the crux of the matter. Research doesn’t follow our whims and while scientists can make guesses as to how long it will take to develop a technology, they can predict neither the unexpected hitch, nor the surprise breakthrough.

Particularly when none of them are willing to openly discuss the possibilities.