In human genetics, a human Y-chromosome DNA haplogroup is a haplogroup defined by differences in the non-recombining portions of DNA from the Y chromosome (called Y-DNA). It represents human genetic diversity based on single-nucleotide polymorphisms (SNPs) on the Y chromosome.
Y-chromosome DNA Testing
The main use of Y-chromosome DNA testing is to be able to confirm relations on the direct paternal line, and exclude people who are not related.
This test is perfect if you have reached a dead end on your direct paternal line. It is also great to try and find relatives if you happen to be adopted and are searching for your biological birth family.
Who Can Test
Why? The Y-Chromosome is only passed down from father to son, women don't have a Y chromosome.
As this image represents Y-DNA is passed down from male to male only.