Sherri Shepherd -- It's Not My Kid and I'm Not Paying Child Support

Sherri Shepherd does not want anything to do with her unborn surrogate baby ... because she believes her estranged husband defrauded her into having the kid in the first place so he could get child support ... this according to multiple sources connected with the couple.

TMZ broke the story ... Sherri and her husband Lamar Sally each separately filed legal docs to end their marriage. The big complication -- a baby will be born this month to a surrogate who signed a contract with Sherri and Lamar.

Now our sources say ... the baby was conceived with Lamar's sperm, but NOT Sherri's egg.

Now here's where it gets tricky. We're told Sherri does not want custody or even to be considered a parent ... because she doesn't want to get stuck with massive child support payments.

Sherri wants a judge to rule she has no parental rights or responsibilities -- which would shut the door to child support. She claims Lamar defrauded her -- that he got her to sign on for a surrogate birth knowing full well he would divorce her and then nail her to the wall for child support.

Our Lamar sources say Sherri tried to get pregnant in vitro and when it didn't work she got deeply involved in the surrogacy process.