Sandra Bullock feels the pressure to get pregnant

Sandra Bullock says she's frustrated beacuse people keep asking why she hasn't had children of her own.

The Proposal star - who is married motorbike enthusiast Jesse James in 2005, is step-mother to his three children, Chandler, 15, Jesse Jr, 12 and Sunny, five and is tired of people asking her why she hasn't had her own baby yet.

She said, "It seems that people want to talk about my uterus. I'm not talking about their vagina or their penis. So why are they talking about my innards?"

The actress said that she avoided getting pregnant earlier in her life because she didn't want to be a selfish mother. "I didn't want to have a child without a partner," she said.

The 44-year-old said that she enjoys the challenges of looking after her step-children and loves them as if they are her own.

She told Britain's The Times newspaper: "A life is a life. Whether or not it came from your body should be secondary, in my opinion. If tomorrow I got home and went, 'Oh my gosh, I'm pregnant,' I'd be like, 'Wow! Isn't the universe amazing?' But what I learnt was that it's being more of a parent to care for a child that's not yours. It's harder."