Queen of Pop Madonna says she doesnt think shes as strict as she should bewhen it comes to her kids. The 53-year-old singer has four children, including daughter Lourdes, 15, sonRocco, 11, adopted son David, 6, and daughter Mercy, also 6. While Madonna admits that shes a toughparent, she thinks she needs to be harder on her four kids, Contactmusic reported. "I think I am, buthonestly I don't think I'm as tough as I should be. I think I need to be maybe tougher. It's hard though.Everyday is a negotiation," she said.When asked about Lourdes smoking episode, the singer said, "I wasn't very happy. Cigarette smokingI'm not very fond of, for anyone, I don't approve of anyone smoking cigarettes, most of all mydaughter."