The Y-DNA STR tests are often used in ancestry, paternity and forensic testing. The test looks at regions on the Y chromosome known as STRs or short tandem repeats. We each have 22 autosome pairs and 2 sex chromosomes. Females inherit two X chromosomes and males inherit an X chromosome and a Y chromosome.
The Y-DNA STR test looks at only the Y chromosome, so can only be tested in men and traces paternal lineage. Females wishing to trace paternal lineage may be able to do so by testing close male relatives. The Y-DNA STR Test offers the options to test between 20, 44 and 101 STR regions present within the Y chromosome.