Services - Y-STR Test

Y-STR Paternal Lineage Test

The Y-STR paternal lineage test is used to determine whether two or more males are
related through their fathers (through the paternal/male line). This test is often used to
provide additional evidence in difficult paternity cases in which the alleged father is not
available for testing. Results of this testing may also be used to confirm the biological
relatives of an adoptee.

The Y chromosome is passed from father to son relatively unchanged through many
generations. The Y-STR test examines specific locations on the Y chromosome to generate
a Y-STR profile for each male tested. Males who are related through their fathers will tend
to have the same or similar Y-STR profiles, and males who are not related will likely have
different Y-STR profiles.

Although Y-STR analysis cannot distinguish between males who belong to the same paternal
line, it is useful for excluding males from an alleged biological relationship. For example, if a
male child and his alleged uncle (alleged father’s full brother) are tested, their Y-STR
profiles must match. If they do not, then the alleged uncle is excluded (not considered a
biological uncle) and the alleged father is probably not the biological father.

There are many scenarios in which the Y-STR test may be used. To determine if this test
will help you in your particular situation, please call 1-800-My-Daddy. One of our caring,
knowledgeable case managers will review the information you provide and guide you through
the testing process.