The latest one comes out of New Mexico: The Daily Mail Online reported 36-year-old Monica Mares and her son, 19-year-old son Caleb Peterson, are "madly in love," thanks to a phenomenon known as genetic sexual attraction.
"He is the love of my life and I don't want to lose him," Mares told the Daily Mail Online. "My kids love him, my whole family does. Nothing can come between us — not courts or jail, nothing."
Mares gave birth to Peterson when she was 16 years old and subsequently gave him up for adoption. According to the Daily Mail Online, they finally connected on Facebook and met as adults in 2015.
Mares said their relationship was normal at first, but then feelings started to develop after they began living together.
"At first I told him, 'I'm sorry I don't know how you are going to react to this. I'm your mom and you're my son, but I'm falling in love with you,'" she told the site. "And he said, 'You know what I am too. I was scared to let you know.' He was falling in love with his mom and I was falling in love with my son."
Their story fits the standard definition of GSA, which is when the child grows up separated from the parent, and then sexual attraction consumes both of them when they're finally reunited as adults. There is not a ton of research on the topic, but a generous estimate reported by one GSA forum said it occurs in as many as half of all post-adoption reunions.
Psychotherapist Joe Soll told Mic in an email that GSA can sometimes happen because the parties are essentially making up for the normal parent-child bond they never got to have.
"Their unconscious minds want to have what they would have had: the intimate closeness, touch, feel of mother and child," he said. "That force of nature is so powerful that they can get carried away without being aware of it and wind up in sexual behavior."
"Their unconscious minds want to have what they would have had: the intimate closeness, touch, feel of mother and child."
Other psychologists say the phenomenon happens because people are often attracted to those who are similar to themselves.
"Genes tend to shape our preferences, talents and attitudes — and familiarity creates comfort, so we look for someone similar," University of Miami psychology assistant professor Debra Lieberman told Good Housekeeping in October. She added that growing up under the same roof typically gives people a "sexual aversion" to their actual family members. "But if you don't grow up together, no aversion naturally develops," she said.
Regardless of how it happens, the resulting sexual relationships it leads to are illegal in most states, although the penalties vary by state. In New Mexico, where Mares and Peterson live, parent-child intercourse is a third-degree felony, according to the American Prosecutors Research Institute.
Still, they stand by their relationship.
"It is every bit worth it," Mares told the Daily Mail Online. "If they lock me up for love then they lock me up. There is no way anybody could pull us apart, and I really do love him."