With the help of DNA testing, Amanda recently discovered her biological father, David, and three younger half-sisters, Marie, Elizabeth, and Jenny.

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Marie and Elizabeth grew up together and say they knew about, but had never met Jenny, and no one, including David, says they knew of Amanda’s existence.

WATCH: ‘There’s A Void From Not Knowing My Biological Father,’ Says Woman Who Hasn’t Seen Dad In 30 Years

While all four women share the same father, each says they’re eager to know what else they might have in common.

“I’m really excited to learn what similarities my sisters and I may have,” says Marie, adding, “The whole nurture versus nature debate rages on.”

On Thursday’s Dr. Phil, Amanda and Jenny meet Marie and Elizabeth in person for the first time.

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