Laws dating back more than 150 years in the US state of Minnesota prohibits married women from committing adultery.
A married woman could face a prison sentence of one year, plus a possible fine of up to 3,000 dollars for cheating on her husband, according to the statute.
"It's completely obsolete and should be repealed," CBS News quoted State Senator Ellen Anderson as saying.
Another law also makes it illegal for single women to have sex at all though neither of the sex laws are enforced.
But not all think they are out of place, including Tom Prichard of the Minnesota Family Council.
Prichard said: "We think they're important. They send a message. When you are dealing with a marriage, it's not just a private activity or a private institution. It's a very public institution. It has enormous consequences for the rest of society."