Baby Harlow is only 8-months-old, but parents Nicole Richie and Joel Madden aren't counting out the possibility of a sibling for their daughter. "If it happens, it happens," Nicole told Extra. The first-time mom also revealed how quickly Harlow is growing up. "She is pulling herself up and standing ... we don't have to burp her anymore," said Nicole. Proud papa Joe added, "She says 'mama' and 'dada.' She says 'dada' when she wants to play. Wants to laugh. And 'mama' is everything else. When we walk into a place, she waves to everyone." The couple is continuing with their charity work, now wanting everyone to text "child" to 9-0999 which will donate $5 to a children's charity they sponsor. They started the Richie-Madden Children's Foundation to help needy mothers last November.