It has been a remarkable year of promise in medical science – from reversing blindness and paralysis to progress in cancer and infertility.
First gene-edited babies, probably.
A scientist in China caused the biggest stir in science for years when he claimed to have made the world's first gene-edited babies.
The twin girls are apparently healthy.
Embryos were produced through IVF.
Then Prof He Jiankui claims he altered the babies' DNA (the blueprint for building their bodies) to protect them from HIV.
But no details of the procedure have been published, so the claims have been treated with a dose of scepticism.
And the announcement provoked huge ethical debate about whether the procedure should have been performed.
- We discussed the claims and the ethics in depth on BBC Radio 4's Inside Science
- He Jiankui defends 'world's first gene-edited babies'
From paralysis to walking
Two groups of scientists have helped paralysed people walk again by stimulating their spinal cords with electricity.
A spinal cord injury – such as through a car crash or sporting injury – stops instructions from the brain reaching the muscles, causing paralysis.
The implants help those lost signals reach their destination.
The techniques remain experimental – but in one case the patient is using the device at home in her day-to-day life.
In the other, there is evidence of the damaged nerves in the spinal cord starting to regrow.
- Electrical implant helps paralysed people to walk again
- Spinal implant helps three paralysed men walk again
90 billion cancer-killers
Judy Perkins's life was saved by a pioneering new therapy for her terminal breast cancer.
She had tennis-ball-sized tumours in her liver and secondary cancers throughout her body and was given three months to live.
Then doctors at the US National Cancer Institute tried an experimental living drug.
Judy's tumour was genetically analysed to identify the rare changes that might make it visible to the immune system.
Out of the 62 genetic abnormalities found, only four were potential lines of attack.
Next, researchers went hunting. A patient's immune system will already be attacking the tumour, it's just losing the fight between white blood cells and cancer.
The scientists screened her white blood cells and extracted those capable of attacking the cancer.
These were grown in huge quantities in the laboratory and about 90 billion were injected back into her.
Other work in the field of cancer immunotherapy won the Nobel Prize for medicine this year.
New womb, new baby
For the first time, a healthy baby was born using a womb transplanted from a dead person.
Previous attempts had failed and some thought it would be impossible.
The mother, 32, was born without a womb due to Mayer-Rokitansky-Küster-Hauser syndrome. The donor had three children and died from bleeding on the brain.
The procedure took place in São Paulo, Brazil.
About six weeks later, she started having periods.
After seven months, fertilised eggs were implanted.
And, after a normal pregnancy, a 6lb baby girl was delivered by Caesarean section.
Doctors have taken a major step towards curing the most common form of blindness in the UK – age-related macular degeneration.
The macula is the part of the eye that allows you to see straight ahead – whether to recognise faces, watch TV or read a book.
The macula is made up of rods and cones that sense light and behind those are a layer of nourishing cells.
When this support layer fails, it causes macular degeneration and blindness.
Scientists devised a way of building a layer of support cells by growing them into a "living patch" just one layer of cells thick.
It was then delicately inserted into the back of the eye.
Growing human eggs
A team at the University of Edinburgh has grown human eggs in the laboratory for the first time.
Women are born with immature eggs in their ovaries that can develop fully only after puberty.
It has taken decades of work but scientists can now grow eggs to maturity outside of the ovary.
It requires carefully controlling laboratory conditions, including oxygen levels, hormones, proteins that simulate growth and the medium in which the eggs are cultured.
The technique could lead to new ways of preserving the fertility of children having cancer treatment.
It also provides an opportunity to explore how human eggs develop, much of which remains a mystery to science.
A test for all cancer?
Scientists have taken a step towards one of the biggest goals in medicine – a universal blood test for cancer.
A team at Johns Hopkins University has trialled a method that detects eight common forms of the disease.
Tumours release tiny traces of their mutated DNA and proteins they make into the bloodstream.
The CancerSeek test looks for mutations in 16 genes that regularly arise in cancer and eight proteins that are often released.
It was tested on 1,005 patients with cancers in the ovary, liver, stomach, pancreas, oesophagus, colon, lung or breast that had not yet spread to other tissues.
Overall, the test found 70% of the cancers.
The vision is an annual test designed to catch cancer early and save lives.
Microbes are the hidden half of our bodies
The immense importance of microbes on our health continues to explored.
This year, the most common type of cancer in children was pinned on our modern germ-free lives.
Acute lymphoblastic leukaemia affects one in 2,000 children.
Prof Mel Greaves, from the Institute of Cancer Research, amassed 30 years of evidence to show the immune system could become cancerous if it did not "see" enough bugs early in life.
This study is absolutely not about blaming parents for being too hygienic.
Rather, it shows there is a price being paid for the progress we are making in society and medicine in areas such as clean water.
The long-term goal is to give children a safe cocktail of bacteria – such as in a yoghurt drink – that will help train their immune system.
The artificial intelligence will see you now
A computer trained to interpret pictures of the back of the eye did as well at diagnosing more than 50 eye diseases as leading experts.
Thousands of scans were used to train the machine how to read the scans.
Then, artificial intelligence was pitted against humans.
Each was asked to give a diagnosis in the cases of 1,000 patients whose clinical outcomes were already known.
Doctors hope artificial intelligence could soon play a major role in helping to identify patients who need urgent treatment.
They hope it will also reduce delays.
And other stories that caught our eye
A baby girl called Benedicte survived after being diagnosed with deadly Ebola when she was only six days old. She is known as the little miracle.
A man in the UK who caught the world's "worst-ever" case of super-gonorrhoea has been cured.
Scientists say diabetes is five separate diseases, and treatment could be tailored to each form.
Scientists say they have settled one of medicine's biggest debates after a huge study found that antidepressants do work.
An unlikely ally has been recruited in order to develop a new flu treatment, introducing your friendly neighbourhood flu-fighting llama.
Gene editing (yes that technique again) has been used to treat Duchenne muscular dystrophy in dogs, marking a significant step towards treating people.
A groundbreaking study uncovered why some patients' cancers are "born to be bad" and are more deadly than others, despite appearing identical.
The food on your plate can alter cancer's growth and spread and scientists hope to take advantage of cancer's "culinary addictions" to improve treatment.
Baby mice have been made with two mothers and no father, by at team of Chinese researchers who had to break the rules of reproduction.
About 70% of women with the most common form of early stage breast cancer can be spared the "agony of chemotherapy" thanks to a new test that analyses the danger of a tumour.
People who have their appendix removed were less likely to develop Parkinson's disease, lending weight to the idea the brain disease starts in the gut.
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