Can Science Pick a Child's Sex?

By Claudia Wallis

Doctors challenge new methods of granting an ancient wish

It is one of nature's most coveted secrets, and over the centuries many have professed to know it. Aristotle had a surefire formula: make love in the north wind to conceive a male child and in the south wind for a girl. Hippocrates had his own prescription--tie a string around the right testicle to stimulate the production of male seed, or the left, if a daughter is sought. Medieval alchemists had an even more exotic recipe for a son: a precoital drink of lion's blood and intercourse under a full moon.

While these theories have vanished into folklore, many prospective parents remain attracted by the idea that they might be able to choose the sex of their children.

In recent years scientists have attempted to take up where the philosophers and alchemists left off. The results have been disappointing. In the 1960s Dr. Landrum Shettles of New York City's Columbia-Presbyterian Medical Center created a sensation with his announcement that gender was influenced by the timing of conception within the menstrual cycle and by the acidity or alkalinity of the female reproductive tract. A douche of vinegar, he contended, would confer an advantage on sperm bearing an X chromosome (for females), while a douche of baking soda would shift the odds toward the Y-bearing sperm (for males). Shettles' theory has now been generally discredited.

The latest method that purports to select the sex of offspring is the brainchild of Ronald Ericsson, founder of Gametrics Ltd. of Sausalito, Calif. Ericsson, who has a Ph.D. in reproductive physiology, is the coauthor, with University of California Obstetrician Robert Glass, of a 1982 book, Getting Pregnant in the 1980s. Gametrics' aggressively marketed method has stirred popular interest, but many scientists are skeptical. "This could be Landrum Shettles all over again," says Dr. Joe Leigh Simpson, a spokesman for the American College of Obstetrics and Gynecology.

Ericsson's theory is based on the fact that sperm carrying the Y chromosome move somewhat faster than sperm carrying the X. To select males, a sample of semen is placed at the top of a glass column containing a solution of albumin, a sticky protein normally present in such bodily fluids as blood and semen. After an hour, more Y-containing sperm than sluggish Xs should have sped to the bottom. The Y sperm are further concentrated by being run through increasingly thicker solutions of albumin. "It's like making them run the Boston Marathon with overshoes on," says Ericsson. The prospective mother is then artificially inseminated with the Y-concentrated sperm. Ericsson claims that of 146 women who became pregnant by this method at clinics licensed by Gametrics, 112 bore males--a success rate of 77%.

Methods of selecting females are also being developed by Gametrics and others.

The Philadelphia Fertility Institute is testing a technique that employs the glass-column race track and Sephadex, a gelatinous powder used to filter impurities from insulin and other hormones. In this case, the X-bearing sperm are the first to reach the bottom of the test tube, perhaps because they are slightly heavier than Y sperm. Results in eleven pregnancies are encouraging: seven girls and one set of male-female twins. Nonetheless, a larger number of pregnancies will be needed before the method is proven.

Gametrics has licensed its patented procedure to 24 fertility clinics around the world, from Gretna, La., to Amman, Jordan. (In the U.S., such technology is not subject to federal regulation.) The clinics pay Ericsson's company up to $15,000 in licensing fees, and many overseas clinics also buy sperm-separation materials from Gametrics. The Gametrics procedure generally costs between $225 and $350, and three or four inseminations are often needed before pregnancy occurs. Customers come to these clinics for a variety of reasons. Many already have children of one gender and wish to ensure that their next child will be of the opposite sex. Families with a history of certain hereditary diseases have a medical reason for sex selection: some genetic disorders, including hemophilia and a devastating form of muscular dystrophy, primarily affect males. There are also cultural motives.

Most Arab and Oriental societies place a high value on male children as laborers, heirs and perpetuators of the family name.

As one Chinese proverb has it, "Eighteen goddess-like daughters are not equal to one son with a hump."

Some independent researchers suggest that the investment is a poor one. Reproductive Endocrinologist Sandra Carson helped test the Gametrics method at Chicago's Michael Reese Hospital. Although early results seemed encouraging, she says, "the final figures were insignificant." In their testing, Reese researchers found that the Gametrics sperm-separation method did not raise the concentration of Y sperm high enough to influence gender.

Ericsson responds to this criticism by charging, "Quality control went to hell at Michael Reese."Dr. Paul Dmowski, who left the program at Reese, also questions standards there. Dmowski, now at Rush-Presbyterian-St. Luke's Medical Center in Chicago, continues to use Ericsson's method and claims a success rate of about 75%.

A number of leading fertility researchers warn that until large-scale scientific tests can provide evidence that sex-selection techniques work, consumers had best beware. "With all of today's sophistication about reproduction, the biology of sex selection remains a mystery," observes Elizabeth Whelan, director of the American Council on Science and Health, a consumer-education group, and author of Boy or Girl?, a 1977 book on sex selection. "Ericsson may be on to something," she allows, "but he hasn't proved it yet." --By Claudia Wallis.

With reporting by Charles Pelton