Fetal DNA gender test from 6 weeks

9 May 2007

Controversy has been sparked in the UK media by the launch of a private fetal gender testing service from the sixth week of pregnancy. International company DNA Worldwide offers analysis of free fetal DNA from a finger-prick sample of the mother’s blood. If Y-chromosomes are detected, it is assumed that the fetus is male; if they are not, the fetus is assumed to be female. A kit that includes materials to take a blood test at home and send to the laboratories costs from £189.95, and parents can check for the results of their test online. 99% accuracy is claimed for the ‘Pink and Blue Early Gender Test’, which has been available in the US since 2006.

The use of free fetal DNA in the maternal bloodstream for early and non-invasive genetic testing is not new; in recent years there has been significant progress towards using the technique for prenatal diagnosis of genetic diseases and chromosomal disorders such as Down’s Syndrome (see previous journal club item). Last year the UK Institute of Child Health has reported results where free fetal DNA was used to identify the gender of fetuses from as early as seven weeks, although this was in the context of an inherited condition that affects girls; early identification of female fetuses permitted prompt prenatal treatment (see previous news story). There are a significant number of genetic disorders that are sex-linked, for example conditions affecting predominantly males such as Duchenne muscular dystrophy and Fragile X syndrome. A non-invasive means of obtaining fetal DNA for genetic testing in such cases avoids the small risk of miscarriage associated with current invasive techniques (amniocentesis and chorionic villus sampling), and is considered a very desirable approach in such circumstances.

However, early gender testing for non-medical (social) reasons is less popular. A statement from the Royal College of Obstetricians and Gynaecologists, whilst acknowledging that finding out the sex of an unborn baby can be exciting for parents, says that sex selection for non-medial reasons is inappropriate, saying: It is to be hoped that the birth of every baby will be a special moment for the parents, regardless of whether it is a boy or a girl. Focus should remain firmly on the health and care of the mother and developing baby, rather than gender”.

Some fear that parents might use the private testing service to allow the selective abortion of fetuses of the ‘wrong’ gender. The company says instead that customers want more time to plan for their baby, although their director did caution that parents who wish to know their child’s gender for medical reasons should seek the help of clinicians, because the company does not provide the counselling that forms an important part of the decision to have prenatal genetic testing for an inherited disease (see BBC news).

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