The embryo essentially creates its own "house" in the beginning stages of pregnancy ... it measures about an inch in diameter. While the photos offer a rarely seen perspective on early development ...

Check out these photos of snake and lizard ... genes are being expressed during this stage of development. A close look at the genitals of a mouse embryo that has been injected with Anolis lizard ...

In an animal's embryonic stage, these gene switches play a predominant role in laying out the animal's basic body plan and perform other early functions. In this slide show, you'll see a striking ...

By contrast, scientists’ knowledge of subsequent events has been extremely restricted. This is the stage (around the fourth day) at which the developing embryo implants into the mother’s womb and its ...

An innovative Weizmann Institute technique for tracking the earliest stages of embryonic development is ... of thousands of individual cells with pictures and physical measurements of individual ...