DNA relationship testing beyond paternity: siblingship, grandparent and immigration
Paternity is the best-known DNA question, but it is not the only one. When the alleged father is unavailable — or the question is about a different relationship entirely — DNA testing can still provide the answer.
The cases
When the alleged father is unavailable
Many relationship cases arise precisely because the alleged father cannot be tested — he may be deceased, untraceable or unwilling. The question does not go away, so the testing works around it, using the DNA his relatives carry:
- Grandparent testing — testing the alleged father’s parents. Between them, both grandparents carry all of the DNA the alleged father could have inherited, which makes this one of the strongest indirect tests.
- Siblingship testing — establishing whether two or more people share one parent (half siblings), both parents (full siblings), or neither.
- Aunt and uncle testing — comparing a child’s DNA with the alleged father’s brother or sister where grandparents are unavailable.
Why marker count can help in these cases
A straightforward paternity test compares a child directly with an alleged parent, and a standard marker panel will usually give a clear answer. Indirect relationships are statistically harder: siblings, grandparents and aunts or uncles share less predictable proportions of DNA, and results are reported as a likelihood rather than a certainty. Analysing more genetic markers — NIVHA’s testing analyses up to 68 — can help in exactly these harder cases, although some cases may still be inconclusive.
Case design matters too. Including a known parent’s sample in a siblingship case, or testing both grandparents rather than one, can strengthen the statistics more than any laboratory technique. This is why relationship cases start with a conversation rather than an order form.
Immigration DNA testing
Where an immigration or visa application depends on proving a family relationship and documents alone are not enough, DNA evidence is regularly used. The receiving authorities need to be sure whose samples were tested, so immigration cases run under strict chain of custody: verified identity documents and photographs for every donor, collection by a neutral party, and collection to the standard the receiving authority requires. Each authority sets its own requirements, so tell us at the outset which one the result is for. Donors in different countries can be sampled locally under equivalent controls, with the analysis brought together in one case.
Timescales: the whole case moves together
Relationship cases involve multiple donors, and results are reported approximately 15 working days after the laboratory receives samples from all parties to the case. One missing donor holds up the whole case — so the practical advice is always to book every collection as early as possible, especially where a donor lives abroad.
Confidentiality
Relationship cases are often sensitive — estranged families, inheritance disputes, immigration decisions. Results are released only to the instructing party, samples travel under unique references rather than names, and nothing is shared beyond the instruction. Testing is arranged discreetly at our Belfast facility, in Derry~Londonderry, in Dublin, or through an approved collector where donors cannot travel — see DNA testing for collection locations.
Common questions
Relationship testing — your questions answered
Can a DNA test prove siblingship?
Yes. Siblingship testing compares the DNA of two or more people to establish whether they share one parent, both parents, or neither. Because siblings share less predictable amounts of DNA than parent and child, these cases benefit from analysing a larger number of markers — and from including a known parent’s sample where possible, which strengthens the statistics considerably.
Can grandparents be tested instead of the father?
Yes. Where an alleged father is unavailable, testing his parents can establish whether a child is biologically related to his side of the family. Testing both grandparents together gives the strongest result, because together they represent the whole of the alleged father’s DNA.
Is DNA testing accepted for immigration applications?
DNA evidence is regularly used to demonstrate family relationships in immigration and visa applications where documents alone are insufficient. The testing must be carried out under strict chain of custody, with identity verified and samples collected by an approved neutral party — the receiving authority needs certainty about whose samples were tested.
How long do relationship DNA results take?
Results are reported approximately 15 working days after the laboratory receives samples from all parties to the case. One outstanding donor holds up the whole case, so arranging all collections promptly is the single best way to keep a case on schedule.
Can NIVHA test before a baby is born?
No. NIVHA does not offer prenatal DNA testing. Testing can be arranged promptly after the birth, including collection arrangements that suit a newborn.
Discuss a relationship case
Tell us who is available to test and what the case needs to establish — we will design the strongest testing strategy for it. Solicitors can request a fee note directly.
This page is a general guide. It is not legal, medical or technical advice. Laws, guidance and laboratory methods change, so check the current requirements for your own case. Last reviewed .