Not surprisingly, our closest biological relatives, the great apes, tend to do best on such an assessment.

Some cases of evolution by natural selection can only be understood by considering how biological relatives influence each other's fitness.

He adds: 'Most of the biological relatives for many people - perhaps most people - will be their ancestors'.

The majority of clients are children who were orphaned, fostered, or adopted seeking to reunite with biological relatives.

Although technically brother and sister, the couple were not biological relatives.

Intellectual resemblance among adoptive and biological relatives.

"In some parts of the world," the report says, "20 to 60 percent of all marriages are between close biological relatives."

Now, she had a new family, and she loved them more than she ever had her biological relatives.

But all her biological relatives are dead or unknown.

Because genetic risk affects biological relatives, contact with these relatives is often essential to collect accurate family and medical histories.