Last fall, Hayek traveled to the African country of Sierra Leone, where she saw the ravages of the disease firsthand. "Before we got to the hotel, we stopped at a hospital. (A woman) was trying to breast-feed the baby, and the baby wouldn't take it anymore. I said, 'I think we shouldn't be here.' As we walked out, two to three minutes later, the baby died," she says. "I'll never forget the look of desperation on that woman's face. How can you not get involved, especially when you have a child yourself?"

Hayek is outspoken and at times eye-openingly candid, as she quietly, thoughtfully recalls encountering a newborn child in a clinic during her trip to Africa. "The baby was perfectly healthy, but the mother didn't have milk. He was very hungry. I was weaning Valentina, but I still had a lot of milk that I was pumping, so I breast-fed the baby," she says, her voice dropping. "You should have seen his eyes. When he felt the nourishment, he immediately stopped crying."

Does she want more children? "Maybe. We'll see. I have to work a little bit. I am 42. I had her at 41. I don't sleep because she doesn't sleep, but I have a lot of energy," she says. "I don't feel like, 'Oh my God, this is too late.' When you turn 40, it's a lot easier than 30. They lied when they said you get old when you're 40. The best is the 40s."