How do you know your partner is not your brother or sister?
Sibling DNA testing is used to establish further evidence of a family relationship in cases where the alleged father is not available for a paternity test. It's also used to verify biological family members of an adoptee or siblings separated at birth.
Siblingship tests are often performed using what's known as a Chain of Custody, a process that documents the test results so that they are legally admissible.
Brothers and sisters having babies with each other?
The world is becoming a far more complicated place, and science is partly responsible. On the one hand, we have invitro-fertilization (IVF) assisting barren couples to conceive, and on the other hand, we have DNA testing to assist in proving the genetic identity of people who may not have been aware that they could be related.
Adoption, too, can create complications for relationships in the future of adopted children. Without knowing whom you are related to by blood, you could find yourself married to your half-sibling, your cousin or your aunt or uncle! In the future, it's not illogical to imagine that sibling DNA testing could become mandatory before a couple is allowed to conceive children of their own. A court would insist upon sighting the documents before granting a marriage license. This would avoid the likelihood of birth defects and blood disorders in the event that a man marries his sister or first cousin, and is far more conclusive than the regular blood test currently required in most states.
Sibling DNA testing is not as simplified as that for paternity, maternity or grandparentage. Siblings inherit varying DNA portions from their mother and father, so it's always advisable to include one or both natural parents in testing. The DNA profiles of the siblings are compared with the parental profiles and help to account for some of the differences observed in the DNA profiles of the siblings.
In fact, sibling DNA testing is reported as a Probability of Siblingship. A professional laboratory can report a probability of above 90% for an inclusion, meaning that the two tested individuals are half or full siblings, or 10% for exclusion, meaning that the tested individuals are not half/full siblings. A result with a percentage of between ten and ninety is considered inconclusive. Some labs won't even accept samples from, or provide services to, the alleged siblings unless one or both parents have also provided samples.
Painless sample retrieval
Blood tests have become redundant where genetic material for the purposes of DNA testing is concerned. Technology has advanced and now all that's required, and in fact preferred, is to obtain a buccal cheek swab from inside the mouth of the people being tested. The fact that it's painless has seen a dramatic increase in the number of tests requested, since it also means samples can be taken at home using a do-it-yourself kit, and dropped off at the lab.
Prenatal sibling DNA testing is sometimes carried out to determine if twins are identical or fraternal. If the same-sex fetuses have the same DNA, then they are identical and can, at any time, donate organs or tissue to each other if the need arises. Fraternal twin sisters and brothers cannot do this with any greater compatibility than any of their other siblings.
Sibling DNA testing is a highly efficient way of finding out answers to family questions that arise out of adoption, infidelity and conception aided by scientific methods. It is affordable, fairly simple and delivers results in around fourteen days.