How Grandparent DNA Test Works?
Three Steps, Its Simple
ORDER TEST KIT
Order ONLINE and we will ship you a DNA sample collection kit on the address provided in the online order in 2 to 3 days. Kits can be shipped to different locations
COLLECT AND SEND SAMPLES
Follow kit instructions to collect DNA samples. Make sure all the sample envelopes are labelled and mail them back to us on the address provided in instructions
RESULTS BY EMAIL
In approximately 7-10 working days, we will send the results of your test by email to the email address (s) on file. We will not discuss/convey results over the phone.
Why Choose Forensics Canada Inc?
Difference between a Home DNA Test and a Legal DNA Test
Science Behind Grandparent DNA Test
A grandparent DNA test is a type of kinship test used to determine the biological relationship between a child and one or both alleged grandparents. This test is especially useful when a parent (typically the alleged father or mother) is unavailable for testing.
1. DNA Inheritance Basics
Humans inherit 50% of their DNA from each biological parent. That means:
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A child shares approximately 25% of their DNA with each biological grandparent.
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This shared DNA is passed down through the parent-child chain: grandparent → parent → child.
2. Type of DNA Tested
Grandparent tests analyze specific regions in nuclear DNA, typically using Short Tandem Repeats (STRs) — repeating sequences that vary between individuals and are highly effective for identity and kinship testing.
3. Testing One vs. Both Grandparents
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Testing both grandparents on the same side (paternal or maternal) provides more accurate and conclusive results because the child’s DNA can be more clearly traced through both grandparents.
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Testing one grandparent can still yield results, but it’s less powerful and often reported as a probability rather than a definitive “yes” or “no.”
4. Statistical Analysis
The test uses genetic comparison and statistical likelihood ratios to determine how likely it is that the tested individuals are biologically related. This is known as a Grandparentage Index or Probability of Relationship, often expressed as a percentage:
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A result over 90% typically supports a biological relationship.
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A result below 10% suggests the individuals are not biologically related.
5. Chain of Custody for Legal Testing
For legal purposes (e.g., immigration, inheritance, custody), the test must follow strict chain-of-custody protocols:
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Verified identification
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Witnessed sample collection
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Secure handling and transport of samples to an accredited laboratory
