MOOC Advertisement

Learn More:
Get An Introduction to Reproduction

Learn more about the the science of reproduction. Dr. Teresa Woodruff, creator of Repropedia, is offering a free online course exploring the world of reproduction.

Get Started!


An embryo is an organism in its early stages of development. In humans, this stage extends from the time an egg undergoes fertilization to eight weeks after fertilization. Beyond that point, the organism is then referred to as a fetus.