Jennifer Lopez wants a child, hubby Marc Anthony doesn't. The news regarding the birth of Violet Affleck on December 1, the daughter of Ben Affleck, J. Lo's former fiancé, with wife Jennifer Garner, is worsening things, giving baby blues to Lopez.

The singer/actress "has wanted to be a mom ever since they tied the knot," says a source. "But while Marc told her he wants children with her, every time J.Lo brings up the subject, he says the time isn't right."

Marc already has three kids: a daughter, Arianna, 10, with a former girl-friend, and sons Cristian, 4, and Ryan, 2, with ex-wife Dayanara Torres.

"Marc says that with his career and his existing kids, he can't devote time to a new baby right now, and that can't make Jennifer happy," the same source adds.

"National Enquirer" is quoting a close friend of the couple: "Jennifer has a strong mothering instinct. Having a baby would mean more to her than winning a Grammy or an Oscar."

Jennifer Lopez, 36, and Marc Anthony, 37, are currently working together on the new film "El Cantante". Hopefully for her, they should soon start working on a child.