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or more than a decade scientists have been saying that a genomic revolution will transform medicine, making it possible to scan all of a person's DNA to predict risk and customize medical care. Well, we've got the machines. Where's the revolution? Getting closer, say researchers at Stanford University, who tested the technology on 12 people. But not quite ready for every doctor's office.

This page shows some key events of human development during the embryonic period of the first eight weeks (weeks 1 - 8) following fertilization. This period is also considered the organogenic period, when most organs within the embryo have begun to form. There are links to more detailed descriptions which can be viewed in a week by week format, by the Carnegie stages or integrated into a Timeline of human development. Online resources available include: individual images of all Carnegie stages, scanning electron micrographs of the earlier stages, cross-sections showing internal structures at mid- and late-embryonic, 3D reconstructions of internal structures, animations of processes, ultrasound scans and information about abnormalites of development.

An MRI scan showed a cluster of what appeared to be lesions in his brain, but specialists were baffled as to the cause. And they were more surprised to find that the lesions kept moving. Brain scans over the next four years showed that the anomaly had travelled at least 5cm through the tissue.

Researchers have long known that women whose families include fraternal twins are more likely to give birth to twins themselves, and they're finally starting to figure out why. After scanning data from nearly 2000 mothers of fraternal twins, scientists from eight countries found two genes that increase a woman's chance of having twins-one that affects hormone levels and another that may alter how ovaries respond to them. The second of these may also have implications for why some women respond better than others to in vitro fertilization.

Embryo Images Normal and Abnormal Mammalian Development is a tutorial that uses scanning electron micrographs (SEMs) as the primary resource to teach mammalian embryology. The 3-D like quality of the micrographs coupled with selected line drawings and minimal text allow relatively easy understanding of the complex morphological changes that occur in utero. Because early human embryos are not readily available and because embryogenesis is very similar across mammalian species, the majority of micrographs that are utilized in this tutorial are of mouse embryos. The remainder are human.

In the animal kingdom, humans are known for our big brains. But not all brains are created equal, and now we have new clues as to why that is. Researchers have uncovered eight genetic variations that help determine the size of key brain regions. These variants may represent "the genetic essence of humanity," says Stephan Sanders, a geneticist and pediatrician at the University of California, San Francisco, who was not involved in the study. These results are among the first to come out of the ENIGMA (Enhancing Neuro Imaging Genetics through Meta-Analysis) collaboration, involving some 300 scientists from 33 countries. They contributed MRI scans of more than 30,000 people, along with genetic and other information, most of which had been collected for other reasons. "This paper represents a herculean effort," Sanders says.