Throng

BROTHERS AND SISTERS IN LOVE:

A powerful and controversial documentary that looks at siblings who have grown up separately and find that when they do meet, they're sexually drawn to each other.

As 20/20 discovers, the phenomenon of Genetic Sexual Attraction is more common than you would ever imagine - it's estimated that half of all later in life reunions lead to a sexual obsession.

You'll meet German siblings Patrick and Susan, who took their fight to stay together to the highest courts in the land; a couple in Britain, who were left to deal with a damaged relationship after the husband's search for his sister took an unexpected turn; an American brother and sister; and in one of the most controversial cases of GSA, a mother and son.