Kourtney Kardashian has found herself in the middle of a shocking paternity scandal. She should be over the moon about the idea of baby No. 4 — but she doesn't know if the child's father is Scott Disick or hot boy toy Younes Bendijma.

Even more shocking, In Touch has learned this the not the first time the 37-year-old has experienced paternity drama.

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In 2013, model Michael Girgenti demanded a DNA test from Kourt after he claimed they slept together in 2009 during her break with Scott and nine months before son Mason was born. She agreed to the test, which ultimately proved Scott was Mason's father.

"Kourtney never questioned that Scott was Mason's dad," a source exclusively revealed. "But this time she's not really sure. This is a nightmare for her."

kourtney kardashian scott disick kids splash

Kourt recently revealed to friends that she's missed her period, and fears she may be expecting. The reality star "doesn't know who the father is," as she reconnected with longtime love Scott, 33, around the same time she was hooking up with Younes, 23.

A source adds the brunette beauty and Scott didn't use a contraceptive during their recent trip to Mexico. “Scott thought a reconciliation was in the cards for them, and they discussed trying for another baby," the insider said.

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The mother-of-three has now found herself in "big trouble," as she also reconnected with Younes during her reconciliation with the reality star. "Scott hit the roof when he heard she was hooking up with him," the source added.

The brunette beauty broke it off with Scott in July of last year, after photos surfaced of him and an ex-girlfriend in Monte Carlo. The couple currently share children Mason, 7, Penelope, 4, and Reign, 2.

Scroll through the slideshow to see Kourt and Scott's cutest moments!