Week 5: Our beautiful ectoderm!

I'm pretty sure we'll look back at these early days and think...boy, was it weird when this kid was just three layers and looked like a sesame seed-sized tadpole. -HMW

How your baby's growing:

Deep in your uterus your embryo is growing at a furious pace. At this point, he's about the size of a sesame seed, and he looks more like a tiny tadpole than a human. He's now made up of three layers — the ectoderm, the mesoderm, and the endoderm — which will later form all of his organs and tissues.