The NFL star and the brain injuries that destroyed him

Before the former American football player Dave Duerson killed himself, he asked that his brain be left to researchers studying head injuries among athletes. What it revealed shocked the scientists

Passive smoking can damage the DNA of sperm, study in mice suggests

If the same is true for human sperm, men could pass genetic defects caused by passive smoking to their children

Daily pill can prevent HIV infection

Groundbreaking studies suggest tablets could help partners of people with HIV protect themselves – secretly, if necessary

Sedentary lifestyle can lead to pulmonary embolism, study finds

Survey of 70,000 nurses shows those who choose sofa over exercise after work more likely to get blood clots on lungs

What a drag … Iceland considers prescription-only cigarettes

Tobacco bill proposes outlawing shop sales, with only doctors allowed to prescribe cigarettes to addicts unable to kick habit

If you’re HIV positive, safe sex isn’t just about condoms

Deborah Jack: With advances in HIV drug therapy, the option of 'treatment as prevention' is a real possibility – though it's not right for everyone

Cervical cancer vaccine a success, says Lancet report

Australian study of injection to protect against HPV virus reveals drop in high-grade abnormalities among under-18s

Choosing to die misses the depth of life

Michael Wenham: Individual 'choice' seemed to trump all in Terry Pratchett's film, which served a cocktail of death disguised as an elixir of life

I was wrong about Trafalgar Square’s meditation flashmob

Naseem Khan: Meditating in public places has always made me uneasy, but this flashmob was half an hour of the purest sanity

UK mother agrees to donate her womb to daughter

Experts divided on whether 'deeply complex' procedure, previously only carried out on animals, is safe for humans