Blood test tells mum boy or girl at 7 weeks

Lindsey Tanner

Boy or girl? A simple blood test for mothers-to-be can answer that question with surprising accuracy at about seven weeks, research has found.

Gender-detecting blood tests have been sold online to consumers for the past few years. Their promises of early and accurate results prompted genetics researchers to take a closer look.

They analysed 57 studies of gender testing done in rigorous research or academic settings -- though not necessarily the same methods used by direct-to-consumer firms.

The authors say the results suggest the blood tests could be a breakthrough for women at risk of having babies with certain diseases, who could avoid invasive procedures if they learned their foetus was a gender not affected by the illnesses.


But the study raises concerns about couples using tests for gender selection and abortion.

Couples who buy tests from marketers should be questioned about how they plan to use the results, the study authors said.

The analysed test can detect foetal DNA in mothers' blood. It is about 95pc accurate at identifying gender when women are at least seven weeks' pregnant - more than one month before conventional methods.

Accuracy of the testing increases as pregnancy advances, the researchers said.

Conventional procedures, typically done for medical reasons, can detect gender starting at about 10 weeks.

The new analysis, published in the Journal of the American Medical Association, involved more than 6,000 pregnancies.