Limb length, cancer, freezing water...

How temperature, rather than genetics, regulates limb length in mammals; the assumption that melanoma follows the usual cancer stem cell model challenged; the discovery of 11 new regions of genetic variation that are linked to cholesterol levels; nagging can save your life – single men are less likely to have prostate cancer screening; how X-ray crystallography has given an insight into the molecular mechanism that prevents eggs being fertilized by more than one sperm; new discoveries that may help control epilepsy and brain damage from a stroke. Plus, in 'Stuff and Non-Science', does boiling water really freeze faster than cold water?