Daughter discovers fertility clinic technician is her biological father

Annie Branum, 21, discovered that the father she grew up with isn't her biological father after taking a DNA test to trace her family history.

Tom Lippert, a technician at the fertility clinic the Branums used to get pregnant, allegedly switched his sperm with hundreds of donors -- including Annie's father, John.

The story of Tom Lippert's sinister swaps has swept the nation, and another family that wants to be identified only as 'Paula, Jeff and Ashley' recently got the difficult news as well. Using Ancestry.com and a DNA test, the family confirmed that Ashley's biological father was Tom Lippert.

Things got even worse when the family looked into Lippert's past. Lippert, who died in 1999, was a convicted kidnapper who once kept a woman in a box and tried to do experiments on her.

The Branums are encouraging other families who used the clinic to test their children's DNA.
One of many fears is that half-siblings could unwittingly engage in romantic relationships.