Tale of Two Mothers

That both of the female baboons at San Antonio's Southwest Foundation for Research and Education had become mothers on Sept. 5, 1975, was hardly unusual. That each was the mother of the same infant male baboon was another matter entirely. In fact, delivery of the baby baboon, reported in Science, was the first birth of a primate resulting from an embryo transplant.* It also may have brought closer the day when a woman who can conceive but is unable to carry a child through a full-term pregnancy could allow another woman to carry and give birth to her infant.

The successful experiment began in Texas in the spring of 1975, when Researchers Duane Kraemer, Gary Moore and Martin Kramen removed a fertilized egg from a baboon five days after she had mated with a male. At that point the egg had moved from her fallopian tube and was floating freely, but it had not yet become implanted in the uterine wall, where there would have been more difficulty in removing it. The fertilized egg was then implanted in the uterine wall of a second female that had been chosen as foster mother because she had ovulated on the same day as the genetic mother (which meant that her uterus was prepared to accept the embryo). The foster mother carried the developing fetus for 174 days and then gave birth to a normal male infant.

Quick Payoff. While many ethical and legal problems remain before embryo transfers become possible in humans, repetition of the Texas experiment could provide some quick payoffs in primate research. In studies of high blood pressure (hypertension), for example, a female baboon with a genetic tendency toward hypertension could be used to provide researchers with many more animals with the same condition. She could be mated once a month, and her fertilized egg removed each time for implantation in a foster mother. The foster mothers would then give birth to infants with a predisposition to hypertension.

* Embryo transfers have been performed successfully in cattle and rabbits for years.

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