Ronald Cole-Turner: Transcending Evolution

Human Germline Modification: A Step Closer?

Human germline modification—often described as "designer babies"—has come a step closer. It has been shown that in nonhuman primates, it is possible to transplant specialized cells that produce sperm. When combined with other steps, this may make germline modification feasible and safe for human use.

The new research involves nonhuman primates. Its purpose is to set the stage for clinical trials in human beings. The goal for using this technique in human beings is to overcome infertility, especially for cancer survivors who were treated with radiation or chemotherapy. In men, that treatment may destroy the ability to produce sperm. If the cancer treatment occurs after puberty, sperm can be stored in advance. But if the treatment occurs before a young boy's body produces sperm, permanent infertility may result.

"Men can bank sperm before they have cancer treatment if they hope to have biological children later in their lives," according to lead researcher Kyle Orwig of the University of Pittsburgh. "But that is not an option for young boys who haven't gone through puberty, can't provide a sperm sample, and are many years away from thinking about having babies," Orwig said, according to a press release from the university.

No medical solution is now available, but the report opens the possibility that, in the future, young male cancer survivors will be transplanted with cells that can restore their ability to produce sperm and to become fathers. To be clear: Orwig's group did not work with human subjects. But by showing that the technique works in rhesus monkeys, they help make the case that it could work in humans and should be tried.

The cells that were transplanted into the rhesus monkeys are called "spermatogonial stem cells" or SSCs. Researchers used frozen or cryopreserved SSCs. In the future, one possibility is that SSCs might be produced from stem cells, such as induced pluripotent stem cells. In addition, the SSCs might be genetically modified before they are transplanted. In nonhuman animals, this would provide a new way to create transgenic animals for research.

Another possibility is that this technique, if used to restore fertility to men who cannot produce sperm, might also be used for human germline modification. In a 2006 article, Hiroshi Kubota and Ralph L. Brinster (a pioneer in developing this technique) suggested that SSC transplantation may be used for precisely this purpose. "Another potential clinical application using human SSCs is GERMLINE GENE THERAPY [Capital letters in original]." They suggest that "germline gene therapy using SSCs will become a promising and feasible approach, although considerable ethical concerns exist."

What makes all this especially interesting is that by transplanting SSCs, researchers may make it possible for fertility to be restored without the use of in vitro fertilization. The Orwig paper suggests this quite clearly: SSC transplantation may be capable of "enabling the recipient male to father his own genetic children, possibly through normal coitus." If the SSCs are genetically modified first, we would have germline modification without IVF.

When human germline modification is suggested, many find the idea frightening. It is generally assumed that religious people will be universally opposed. That is not true, not even among Catholics.

What the official Catholic position opposes is the destruction of human embryos or even their creation outside the human body, which IVF requires. The Vatican is not opposed to using high-tech medicine to create healthy babies.

In 2004, this is what a Vatican commission had to say: “Germ line genetic engineering with a therapeutic goal in man would in itself be acceptable were it not for the fact that is it is hard to imagine how this could be achieved without disproportionate risks especially in the first experimental stage, such as the huge loss of embryos and the incidence of mishaps, and without the use of reproductive techniques. A possible alternative would be the use of gene therapy in the stem cells that produce a man’s sperm, whereby he can beget healthy offspring with his own seed by means of the conjugal act.”

It almost sounds here like the Vatican was suggesting the technique that is being developed. It should be noted that this statement was released while John Paul II was pope. It was drafted by a commission headed by Cardinal Ratzinger, who is now Benedict XVI.

We should not expect Catholics or any other religious community to lead a chorus of praise for human germline modification. At most, we might expect guarded comments from religious leaders, coupled with the demand that this technology be limited to therapy and not used for enhancement. But the key point is this: If human germline modification technology is developed, religious leaders may actually be open to its use.

But if it is developed for therapy, who really thinks it will be limited in that way? If it works to create a healthy baby, why not use it to create a better baby?

A version of this post first appeared on Enhancing Theology.

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