Embryonic stem cells, dating rocks on other celestial bodies and controversies on human guinea pigs were some of the most popular in-depth stories of the year.

Stem-cell research: Never say die

With a history of public blunders, can Advanced Cell Technology make embryonic stem-cell therapies a reality?

11 January 2012

Human experiments: First, do harm

In the 1940s, US doctors deliberately infected thousands of Guatemalans with venereal diseases. The wound is still raw.

8 February 2012

The split brain: A tale of two halves

Since the 1960s, researchers have been scrutinizing a handful of patients who underwent a radical kind of brain surgery. The cohort has been a boon to neuroscience — but soon it will be gone.

14 March 2012

Life-changing experiments: The biological Higgs

Biologists ponder what fundamental discoveries might match the excitement of the Higgs boson.

28 March 2012

Neuroscience: The mind reader

Adrian Owen has found a way to use brain scans to communicate with people previously written off as unreachable. Now, he is fighting to take his methods to the clinic.

13 June 2012

Planetary science: The time machine

Dating features on the Moon and Mars is guesswork. Scott Anderson is building a tool to change that.

25 July 2012

Data teleportation: The quantum space race

Fierce rivals have joined forces in the race to teleport information to and from space.

5 December 2012

Nuclear energy: Radical reactors

For decades, one design has dominated nuclear reactors while potentially better options were left by the wayside. Now, the alternatives might finally have their day.

5 December 2012

Replication studies: Bad copy

In the wake of high-profile controversies, psychologists are facing up to problems with replication.

16 May 2012

Endangered species: Sex and the single rhinoceros

Conservationists are taking heroic measures to restore the fertility of a three-footed Sumatran rhino. But some ask whether this is the right way to save an endangered species.

30 May 2012