A Jackson, Mississippi, couple made a startling discovery after visiting a fertility clinic: they’re brother and sister.

The names of the couple as well as the doctor are not being disclosed due to patient confidentiality rules. Details about the case however were given to the Mississippi Herald and published online.

“My first reaction was that they must have been less-closely related; perhaps they were first cousins, which does happen sometimes,” the doctor told the Mississippi Herald, “However, looking closer at the samples, I noticed there were way too many similarities”.

The couple, fraternal twins, were separated at birth after their parents were killed in a car crash. After no close relatives agreed to take them in they were put up for adoption.

Both were adopted by separate families and each grew up unaware of the other’s existence. The two reconnected in college and began a relationship, eventually getting married. The doctor at the fertility clinic speculates the circumstances were the result of a filing error by the adoption agencies involved.

The couple’s initial attraction, ironically, was to each other’s similarities and background. They reportedly said that people had often remarked how much they looked alike and about the coincidence of their shared birthday. “They burst out laughing when I asked them if they knew they were twins,” says the doctor.

Reality soon set in and now the couple must decide on their future. It is illegal for siblings to marry in the state of Mississippi but given the circumstances it’s unlikely charges will be filed.

The discovery was made when the couple applied for an in vitro fertilization program. A DNA profile was taken from each and upon closer examination a lab technician noticed they were nearly identical.

“I really hope they can work something out. For me, it’s a particularly unusual case because my job is all about helping couples conceive a child.” said the doctor, “This is the first time in my career that I’ve been glad I haven’t succeeded in that regard.”

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