What will the test report say if other relationships are being examined?
It serves well to remember that no indirect relationship test will give a conclusive result akin to a paternity test. So sibling, avuncular, and grand-parentage tests can give an indication of a biological relationship, but must be taken together with other evidence if a relationship is to be surmised.
For example, full siblings have the same biological mother and father. Half siblings share only one biological parent, which can either be the mother or the father. Our sibling-ship analysis begins with the assumption that the half sibling or full sibling relationship is equally likely (50% probability). The DNA evidence we derive is used to test the two hypotheses. One will usually be shown to be more strongly in support of a particular hypothesis, rather than the other. If we show a probability in excess of 80 %, then that will support a particular hypothesis, for example, that the individuals are more likely to be related as full, rather than half, siblings.
More powerful statistics are generated when one of the biological parents is available for testing, usually the mother of the tested child. On occasion we may gain an inconclusive result. That is, we can demonstrate a relationship but that the evidence does not strongly support one or the other hypothesis.
Sometimes a potential half sibling relationship may effectively be excluded yet still be related, because they have by chance not inherited sufficient of the shared parents DNA. Any data we derive will be reviewed by one of our senior geneticists and our final report will clarify these points for you.
Testing of cousins is not recommended, as the relationship is too distant for a conclusive result to be presented. We do not perform such testing.