From May to August 2022, 157,580 deaths were recorded, 20.5% more than in the same months of 2019, before covid. This increase in mortality was mainly among people aged 75 years and older. Of the causes of death directly related to the heat, heat stroke and dehydration stood out. These are some of the provisional data published by the National Statistics Institute (INE) in relation to deaths in 2022. Covid-19 was the most frequent cause of death, with 31,559 people dying, 20% less than in 2021.

We compared semen analyses of 45 patients before and after mild covid-19 infection. We found a significant decrease in sperm volume, sperm concentration, total and progressive motility and vitality after infection, and that these effects may be long-term.

An analysis of data published in the journal General Psychiatry with more than 66,000 diagnoses of gender dysphoria, mostly made in the United States, concludes that prevalence increased between 2017 and 2021, and that the median age decreased over the same period from 31 to 26 years.

A research team describes in Nature the presence outside the solar system of CH3+, a cation that could react with other molecules to form complex organic molecules. Its role in interstellar organic chemistry was described decades ago, but until now it had not been observed outside the solar system. The team, which includes co-authors from the CSIC's Institute of Fundamental Physics and the National Astronomical Observatory in Madrid, based their work on observations from James Webb Telescope.

If effective strategies are not developed, more than 1.3 billion people will be living with diabetes by 2050, some 800 million more than today. This is according to the lead study in a set of papers published in The Lancet and The Lancet Diabetes & Endocrinology. In addition, 75% of these people will live in low- and middle-income countries, which is largely due to "structural racism and inequality", according to the editorial accompanying the studies.

This week, Japan began testing a new facility designed to discharge treated wastewater from the Fukushima Daiichi nuclear power plant into the Pacific. The water has been used to cool the melted reactor. After filling more than 1,000 tanks, the storage should reach full capacity early next year.

A commentary published last Friday in the journal Molecular Psychiatry, signed by more than 30 researchers, challenges the conclusions of the systematic review published in the same journal in July 2022, in which the authors concluded that there was no evidence that low serotonin levels cause depression. The researchers in the new paper blame the earlier study for flaws in methodology, among other weaknesses.

Results of the first phase of a project to develop an artificial placenta in an animal model, to help extremely premature babies (born at 6 months gestation or less), were presented to the press today. The project is led by BCNatal, a fetal medicine research centre in Barcelona, with funding from the "la Caixa" Foundation, which has renewed its support for the second phase of the project. 

The Guardian newspaper reported on Wednesday that Magdalena Zernicka-Goetz's team had announced the generation of synthetic human embryos from stem cells at the annual meeting of the International Society for Stem Cell Research in Boston. The author later denied on Twitter that they were synthetic human embryos and spoke only of models, warning that it was pending publication in a scientific journal. The day after the publication in The Guardian, and as reported in El País, Jacob Hanna and his team published a preprint - a publication that has not been peer-reviewed - in bioRxiv on models of human embryos generated from stem cells without genetic editing. A few hours later, Zernicka-Goetz's team posted their preprint on bioRxiv.

The latest episode of competition between research groups working on the same topic, a very common situation in science, should not distract us from the actual achievement: synthetic human embryos, in the laboratory, made from stem cells, up to a post-implantation stage. Now, we must decide what status or condition we will grant to these synthetic embryos. Once again, science is leaping forward and testing the limits of the laws, posing new ethical challenges for us to solve.