Siblingship Testing

A sibling test can verify if two people are likely to be full or half siblings. It impossible to determine with 100% certainty whether two people are siblings without having either one or both of the parents’ involvement, however DNA tests help determine if two people are likely to be biologically related.

It’s a test that can be requested by a parent or the siblings themselves (if they’re over the age of 18 or a legal guardian is giving consent for the minor(s) involved).

You do not need DNA from a parent to do a sibling test, however if you do have a parent willing and able to provide a sample, it will produce more accurate results. If a mother is unable to participate in the DNA test, a grandparentage test may be more definitive.

This is how it works in all relationship DNA tests – the more people willing and able to be tested, the merrier (and better, accurate test results)!

What types of sibling DNA tests can we do?

Here’s what we can check for at Test Smartly Labs:

  • Full siblingship – if you and your sibling know you share the same mother but want to check if you share the same father (who is unable to get tested.) We can also run this test if the mother is unable to participate (however her participation will significantly increase the accuracy of the test).
  • Half siblingship – if you and someone else know you have different mothers but want to see if you share the same father (who is unable to get tested). If one or both moms will participate in the test, the results will be more conclusive; however, parental participation is not a requirement for the test to be run.

Once all samples have been collected, results should come within 5-6 days.

How does a sibling test work?

As an individual, 50% of your genes came from your mother and 50% came from your father. If you have a full sibling, they too received 50% from your mom and 50% from your dad.

But unless you’re twins, you don’t look alike! That’s because genes express themselves differently in people.

Let’s pretend a gene is like a dice. It’s one block with six different sides (in genetics this is called an allele.) (Note: genes don’t necessarily have 6 variations, some have more and some have less. This is just an example.)

When a child is conceived, it’s like both the mother and father rolled the dice. For you, say the dice landed on a 2 and that’s why you have brown hair… but for your sibling it landed on a 4 and that’s why you’re a redhead.

Although you and your sibling have genes expressing themselves in unique ways (one shows a 2 and the other shows a 4) – making you different from one another – you received the same set of genes (the same dice were rolled) from the same two people and DNA testing can verify that.

In the case of a half sibling, you won’t have as many genes in common; however, DNA tests can look and see if there are enough matching genes to prove you share a biological mother or father.

Test Smartly Labs can work with any family situation to help get siblings tested. To get started, contact us.