"They are arguing a lot because Tom feels he is getting on in age [he's 47] and he thinks Katie owes it to him and Suri to get pregnant. He says he would be in his 60s while the child was young and that's still just about OK to share in the child's life," the Daily Express quoted a source as saying.
The insider added: "Katie feels Tom is more wound up about this than he's ever been and relations between them are at a really tricky stage. She's only 30 and she's not sure about having another baby right now but then she feels guilty about Suri being an only child, especially as she grew up in a big family herself."
According to sources, Cruise's Wichita co-star and beauty Cameron Diaz has increased the tension between the two after exclaiming that it would be nice for Suri to have a brother or a sister.
The insider said: "Cameron is besotted with Suri and innocently said to Tom in front of Katie how nice it would be for her to have a sibling to play with. She didn't know what a hot potato the subject is between the two and after Cameron left their house they had another argument."
Cruise's insistence on having another baby may be because he envies David and Victoria Beckham's large family, believes the source. The snitch further added: "Tom gets on really well with David and once they had a night in together watching a couple of films while the Beckham boys wandered in and out giving their dad a kiss and a hug. It made Tom quite envious. He said he would really love to have a little brother for Suri."