Veteran actor Robert Duvall is bemused he has never become a father, and presumes he must be infertile. The 76-year-old is on his fourth marriage, to 35-year-old Argentine actress Luciana Pedraza - but has never had children, despite trying for many years. He says, "I guess I'm shooting blanks. (I've tried) with a lot of different women, in and out of marriage. I thought of adoption, but (my wife and I) haven't yet."