First came the home pregnancy test. Now here comes the home gender test.
A new blood test being marketed to American women offers them the chance to find out whether they are having a boy or a girl almost as soon as they realize they are pregnant, as early as five weeks along.
Just two or three days after mailing the test overnight to a Lowell lab for processing, a pregnant woman can know what color to paint the nursery -- or even decide whether to get an abortion if she wants a child of the opposite sex, a prospect that worries ethicists.
The $275 test works by detecting and analyzing fetal DNA floating in the mother's blood, a method that researchers say holds promise for serious clinical uses, from cancer testing to prenatal diagnosis of Down syndrome.
The test, called the Baby Gender Mentor, is meant for ''the type of woman who can't wait to open Christmas presents," said Sherry Bonelli, president of Mommy's Thinkin', the company that is marketing the test at an online pregnancy store.
But ethicists asked about this early, commercial application of fetal DNA testing say it raises concerns about sex selection, particularly in societies and immigrant groups where boy babies are preferred.
''You can tiptoe around it, but the fact is that if you're sending information about sex, then you're in the sex-selection testing business," said bioethicist Arthur Caplan of the University of Pennsylvania. He would not ban the test, he said, but ''I would condemn it."
Sex selection, mainly using ultrasound tests and abortion, is considered a growing and potentially destabilizing problem in parts of Asia. In its most extreme form, parents kill girl babies. In China, it has led to an imbalance of about 120 men for every 100 women; and in India, one recent report from an affluent area of New Delhi found that for every 1,000 boys born in 2004, only 762 girls were born.
America is different, of course. ''There's always that slim possibility" that a woman could use the new gender test for sex selection, Bonelli said, ''but I think the numbers are so small it makes that concern insignificant."
Still, US bioethicists and pregnancy doctors tend to discourage sex selection, with the major exception of its use by couples whose offspring may inherit sex-linked diseases. Sex selection ''may ultimately support sexist practices," according to the official ethical position of the American College of Obstetricians and Gynecologists.
Currently, most expectant mothers have the chance to get a good -- though not always guaranteed -- idea of a fetus's gender when they have a routine ultrasound to check its health when they are about 16 weeks pregnant. Women who have an invasive procedure such as amniocentesis to check the fetus's chromosomal makeup for defects can also find out the gender for sure, usually at about three or four months. Those procedures carry a slight risk of miscarriage, however.
A blood test for fetal DNA, in contrast, offers a noninvasive way to peek at the fetus's genes. One researcher has even suggested that in the future, it may be used to perform a complete genome scan on an embryo.
Baby Gender Mentor hit the market June 17 with an exclusive announcement on NBC's ''Today."
Scientific work on fetal DNA analysis has been racing ahead since the late 1990s, when researchers first discovered, to their amazement, that in a pregnant woman's blood, some ''cell-free" DNA -- DNA that is floating around in clumps rather than contained in the nucleus of a cell -- comes from the fetus. The fetal DNA is believed to get into the mother's blood through the barrier of the placenta.
The test includes a finger-prick kit for collecting a blood specimen, which is then sent to the lab for analysis. The lab amplifies the DNA and then looks for the presence of a Y chromosome, which only males have. Presence of the chromosome generally means the fetus must be male; its absence means a female.
Technically, that is ''a piece of cake," said Dr. Charles R. Cantor, professor of biomedical engineering at Boston University, who cofounded
''The sex test is very controversial because it's not clear that you want to broadly facilitate the ability of people to sex-select embryos at a very early stage," he said. ''It's potentially abusable."
Cantor said he, like many other researchers, is much more interested in developing tests for diseases, such as cystic fibrosis and Down syndrome. Similar technology could be highly useful in cancer tests, he noted, because tumors -- like fetuses -- release free DNA into the bloodstream. So a cancer patient who today must undergo a painful bone-marrow test may, someday soon, be able to get by with a simple blood test.
The broader potential is not lost on Acu-Gen Biolab, the Lowell laboratory that is handling the Baby Gender Mentor tests. Its scientific director, Dr. C. N. Wang, said the gender tests are meant in part to demonstrate the power of an innovative DNA technique.
That technique allows the lab to reach definitive results from a drop of dried blood instead of the fresh blood usually required by medical diagnostic tests, Wang said. Scientific journals have reported near-perfect accuracy on similar tests, and the lab promises 99.9 percent accuracy or double money back. But Wang said the company is not yet ready to publish its data on the technique and its accuracy. Publication would ensure that other scientists reviewed the data.
''The point here is that we're using a very simple service to demonstrate an amazing aspect of DNA that has never been thought about," he said. Acu-Gen, too, he said, is pursuing possible uses of the technology in cancer and prenatal diagnosis.
Since the announcement on ''Today," thousands of the tests have been ordered, Wang said. The US Food and Drug Administration told the company that it did not need approval because the test would not be used for a medical diagnosis, he added.
It remains to be seen how big the market for a gender test will be among the roughly 4 million American women who give birth each year. (Bonelli said that her company will ship only to the United States.) The test's ads cite estimates that more than half of expectant parents want to know the baby's sex in advance.
A Toronto lab, Paragon Genetics, has been offering a similar test for about two years to expectant mothers, though it starts at 10 weeks instead of five, costs $390, requires a vial of fresh blood, and gives results in 10 business days instead of 48 hours. The lab's director, Yuri Melekhovets, declined to disclose the level of demand, saying he feared attracting competitors.
The Baby Gender Mentor setup concerns him a bit, he said, because, judging by his experience and reports published in journal articles, it appears that fresh blood works best.
He is aware of the potential ethical concern of sex selection, Melekhovets said, but contends that the problem is not the product, but what is done with it.
''We supply the information," he said, ''and what you do with the information is up to you."
Carey Goldberg can be reached at email@example.com.