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Biological Gender Determination

Do you want to know the biological gender of your baby? Most routine scans can give you a good indication of the baby’s biological gender around 16 weeks. However during pregnancy the placenta releases the baby’s DNA into the mother’s blood. Unlike most DNA, which is found inside a cell’s nucleus, these fragments are free in the circulation and called cell-free DNA (cfDNA). There needs to be sufficient foetal DNA in the mother’s circulation for the test to work (usually by 10 weeks of pregnancy). Testing your blood for foetal DNA and the presence of Y-chromosomal DNA can show if you are expecting a boy or if it's more likely to be a girl.

Available Soon – Biological Gender Determination (BGD)

  • Includes sampling at a location of your choice
  • Completely safe to mother and baby, no risk of miscarriage
  • Testing from 10 weeks of pregnancy
  • Results in 7 working days
  • Testing performed in a UK Forensic Genomics laboratory using highly
    sensitive and accurate technology for human identification


This test will reveal the gender of your child before the child is born. This can be done additionally to the ultrasound determination when you really want to be sure about the biological gender or you can do it even before an ultrasound can show you the sex of your child. You can do this test when you are ten weeks in by sending us a blood sample and we will analyse the tiny fragments of fetal DNA in your blood. If you will have a boy we will find tiny pieces of the male determining Y-chromosome, if you get a girl we will find no Y-chromosomal DNA.

Ordering this kit you will be send a sampling kit and an instruction to contact our phlebotomy group. They will visit you at a location of your choice to take a blood sample. The samples is then returned to the laboratory where results will be available 7 working days later.


For the biological gender determination we need a blood sample of the mother. When you order and pay for the test online it will automatically send a notification to our phlebotomists who will contact you to make an appointment for them to come and collect your sample. They will bring the collection kit with them.

When you are pregnant tiny pieces of the DNA from your developing baby are present in your bloodstream. We analyse these pieces and search for male DNA in your blood. If there is no male DNA present you are highly likely to be expecting a girl. If there is male DNA in your blood you are expecting a boy. The test cannot identify a possible sex chromosome abnormality.

The presence of the Y-chromosome in the mothers blood can be detected at extremely low levels but no molecular test will ever be 100% accurate. There are a few rare circumstances where the test will not work. They include: a sex chromosome abnormality, if you have had a bone marrow or organ transplant by a male donor, or if you are not over 10 weeks pregnant.

Ten weeks from the date of your last menstrual period.

No. This test only requires a single blood tube from the mother’s arm.

If the ultrasound shows something different this might be caused by the fact that not enough DNA of the foetus was  present in your blood or the ultrasound is wrong. The actual gender might not be determined until the baby is born. This can be caused by a few factors like a discrepancy between visible and biological gender and the possible issues described in “how accurate is the test?”.