After a few years of marriage, some couples hit obstacles, everything from infidelity to compatibility issues, but the news one man just found out about his wife, the mother of his two children, is something he never expected - that she is his sister.

It might seem unlikely but the reason it happened is because the man was adopted at birth and never knew anything about his biological parents. However, when his wife of six years needed a kidney, he underwent tests to see if he would be a viable donor. He explained on Reddit that he found out he is indeed a match, but the doctor wanted to do additional testing due to what he described as "some information from the HLA (human leukocyte antigen) tissue results." The man said, "I didn't think much of it and agreed."

However, when the results came back, he learned he and his wife had an "abnormally high match percentage." This confused him but the doctor went on to say that "because of how DNA is passed down through generations, a parent to a child could have at least a 50% match and siblings could have a 0 to 100% match." The doctor stated it was "rare" to have this high a match as husband and wife and that the pair are related and likely brother and sister.

Unsure of what to do, the man asked commenters to help. One wrote, "You already have kids and they are assumedly healthy since you didn't mention any crazy abnormalities. If you're happy, you're happy. Donate the kidney to your sister-wife and continue being great parents to your children." Another said, "I mean at this point you are married with children already - you can't take that back so I don't see much point in blowing worlds up," while someone else wrote, "Everything's been great this long, no point changing it."

No word on what the man has decided to do but you can see more of the comments on the post on Reddit.