Rob Kardashian makes startling sex confession

Rob Kardashian has told his sister Khloé Kardashian and friend Malika Haqq that he can no longer father children.

The 37-year-old reality star is already father to seven-year-old Dream Kardashian who he shares with ex-fiancée Blac Chyna, 36.

In scenes that aired in the latest episode of The Kardashians, Malika confided in Khloé that she is desperate to have more children and has been considering using a sperm donor after splitting from O. T. Genasis, who is the father of her son, Ace.

Explaining her thoughts, Malika said, "I just think I might have to go to the sperm bank. You know... I don't want to be, like, 42 or 45 and pregnant. I fought for this body. But if I'm gonna carry, it has to happen almost now because I'm not a spring chicken, you know."

Offering her support, Khloé then suggested that Rob could be a donor - highlighting that the pair already share a past romance.

Calling her brother, Khloé announced, "I'm with Malika. Real serious question though. Like, Bible serious. Malika wants to have another kid. And she was gonna go to a sperm bank to get sperm. But I just said 'Why not get it from you?' You don't have to (have sex)... you just put it in a cup."

However, Rob claimed, "I can't c*m anymore," and repeated, "I just said I can't c*m anymore. What don't you get?"

Refusing to take this as a viable answer, Khloé then said, "Well, we have time to prepare her womb, so we could have time to prepare your penis. You just simmer on this conversation, ok?"

But Rob insisted again, "I just told you, I can't c*m," prompting Khloé to end the call.

The older Kardashian sibling appeared unconvinced by Rob's excuse, however, and said in a testimonial video, "My brother is just, like, he's just disgusting and we can't ever just talk normal. But I don't think there's a problem."