20 weeks!!

Your babies weigh about 10 1/2 ounces now. They're also around 6 1/2 inches long from head to bottom and about 10 inches from head to heel — the length of a banana. (For the first 20 weeks, when a baby's legs are curled up against his torso and hard to measure, measurements are taken from the top of his head to his bottom — the "crown to rump" measurement. After 20 weeks, they're measured from head to toe.)

They're swallowing more these days, which is good practice for their digestive system. They're also producing meconium, a black, sticky by-product of digestion. This gooey substance will accumulate in their bowels, and you'll see it in their first soiled diaper (some babies pass meconium in the womb or during delivery).