Stories by Mariana Lenharo

Some clinicians are pushing to broaden testosterone use, but there is debate about its benefits and risks

Representatives of more than 50 nations gathered in Santa Marta, Colombia, this week at what was billed as the first global summit on phasing out fossil fuels. A panel of scientists will be advising them

Older people with exceptional memory have a surprisingly high number of young neurons, a study finds

Fitness influencers promote superhigh-protein diets, but studies show there’s only so much the body can use

Female Aedes mosquitoes signal that copulation can proceed by subtly extending their genitalia

Maria Branyas Morera was the oldest person in the world when she died. Scientists analysed her genes, metabolism, and more

What to know about the three shots under scrutiny by RFK Jr’s advisers and the data behind them

A new analysis uncovers seasonal patterns of dengue, a mosquito-borne disease, across the Americas, which could help scientists anticipate future outbreaks

Insights from human brains could inform how scientists search for awareness in all its possible forms

A heart attack unleashes immune cells that stimulate neurons in the brain, leading to restorative slumber

Three scientists are honored for developing a class of blockbuster weight-loss drugs. Is a Nobel prize on the way?

The Oropouche virus, which causes a disease nicknamed “sloth fever” for one of the animals that can be infected, has seen its first cases in the U.S.

As the daughter of a cancer researcher, Kamala Harris would bring a lifelong familiarity with science to the presidency, experts say

The neurons that produce a sick feeling and food aversion are distinct from those that induce a feeling of fullness

A declaration signed by dozens of scientists says there is “a realistic possibility” for elements of consciousness in reptiles, insects and mollusks

An Alabama court ruling that human embryos outside the uterus should be regarded as children has raised concerns among doctors and scientists about the future of the fertility treatment in vitro fertilization

Recent studies evaluate risks associated with drugs such as Wegovy and Mounjaro

The antiviral drug ensitrelvir, which has not been approved outside of Japan, shortens sensory problems

Neuron activity shows that the brain uses different systems for counting up to four, and for five or more

Researchers publicly call out theory that they say is not well supported by science, but that gets undue attention

A checklist derived from six neuroscience-based theories of consciousness could help assess whether an artificial intelligence system achieves this state

Clinical-trial data suggest that semaglutide, sold under the name Wegovy, slashed risk of heart attacks and other cardiovascular incidents in a trial

The U.S. Food and Drug Administration has approved the use of the oral contraceptive Opill without a prescription, increasing access to birth control at drug stores and online retailers

The World Health Organization has declared that COVID is no longer a “public health emergency of international concern” but cautions that it is still an ongoing health issue