Some say you become a mother the moment you see that positive symbol on the pregnancy stick. Others say it's the instant you hold your newborn or clean a messy diaper for the first time. The second in time you experience the joy and magnitude of motherhood is different for every woman. We've asked celebrity mamas to answer our four little questions about motherhood and the rebuttal to our "you know you're a mother when...?" question is ever cheeky, endearing, sweet, and comical. In honor of Mother's Day learn when Kelly Ripa, Soleil Moon Frye, Molly Shannon, Rebecca Romijn, Jenna Elfman, Jennie Garth and Tori Spelling felt their "I'm a mom!" moment. Spoiler alert: four out of seven mamas reference bodily fluids.