Why would you Need an X Test?

X chromosome testing is usually carried out between sisters. This test is used in situations where female participants need to know if they share the same biological father (Note that only females can carry out an X chromosome test).  This test seeks to confirm whether or not there is a match between the X chromosome profiles of the people tested.

If this is the test you require we need to establish the following:

  1. Do the females involved share the same biological mother?
  2. Are all the people required for the test available?

If females have the same biological mother, we can carry out the test by comparing the X chromosome profiles of the people taking part. In this example, we will need a sample of the mother (tested at additional cost).

If females taking part have different mothers, we can carry out the test without the sample of the mother.

Our X chromosome Test includes:


  • Testing of 2 females
  • A home DNA sampling kit which you will use to collect your own DNA samples (the Kit arrives to your chosen address and packing is non-descript)
  • Confidential results which can be downloaded online, sent by email or by post (the latter two options are on request and hard copy is subject to a small additional fee)

Paternal Grandmother & Granddaughter

The X chromosome test can be used between paternal grandmother and granddaughter as they must share one X chromosome. This shared X chromosome is the one that the grandmother passed to her son and he, in turn, passed to his daughter. We only need DNA samples of the paternal grandmother and granddaughter for this test. We require no other samples in this particular case.

X Chromosome Test Results

If the test participants share the same biological father, our X test will show matching profiles. We extract 10 markers in this test and would normally expect a match at each of these genetic markers for a conclusive result.

Rare cases of X chromosome mutations result in different regions appearing as a mismatch resulting in less than 10 matching markers between profiles of the test participants.  But this does not mean the individuals tested do not share the same father. If we identify between 1 and 2 mismatches we provide an inconclusive result (which does not exclude the possibility of the people tested sharing the same father). If we locate 3 or more mismatches, the result conclusively shows that tested parties do not share the same dad.

Using our Home Kit

Once your order has been processed, our home sample collection DNA kit will promptly be sent to any address you specify. Your kit contains swabs for 3 people as well as instructions and consent forms (these forms need to be filled in and returned with your samples; without these forms completed, we cannot carry out the test).

Swabs need to be rubbed inside the mouth against the lining of the mouth known as the mucosa. This lining is formed by millions of cheek cells which will stick to the tip of the swab.

If test participants live in different locations we can send out multiple kits.

Note: We can only guarantee standard result turnaround time when testing takes place solely using mouth swab samples. Using a discreet sample for your X chromosome test may lead to an increase in turnaround time.

Order Now
This website uses cookies to give you a better user experience. By using this website or closing this message, you are agreeing to our Cookies notice