How big is the baby?

There's a baby website that equates the size of the baby each week to a different fruit or vegetable. Fruits and vegetables are something people really know and understand, so it helps them be able to envision just how big (or small!) the baby is. So far, the baby has grown from a poppy seed to a sesame seed to a lentil to a blueberry to a kidney bean to a grape, and finally, this week, the baby is the size of...

... a kumquat!