A review of 25 studies conducted over nearly 50 years has found an association between insecticide exposure and lower sperm concentration. According to the authors, "insecticides are a public health concern for all men, who are exposed mainly through consumption of contaminated food and water". The results are published in the journal Environmental Health Perspectives.
Spermidine is a naturally occurring compound that has been linked to increased longevity in some organisms. New research shows that supplementation with this compound improves oocyte quality and fertility in older female mice. If its action and safety in humans is confirmed, the authors argue that it could serve as a therapeutic strategy to "improve the reproductive outcome of older women, either through natural pregnancy or assisted reproductive technologies". The results are published in the journal Nature Aging.
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.
A scientific team has generated synthetic human embryos using stem cells, reports the British newspaper The Guardian. The authors, who announced the breakthrough at the annual meeting of the International Society for Stem Cell Research in Boston (USA), say the model embryos, similar to those found in the early stages of human development, could be crucial for research into genetic disorders and the causes of miscarriages, according to the newspaper. However, the work also raises ethical and legal issues.
Reaction: stopping endocrine therapy to try to get pregnant after breast cancer does not worsen prognosis
A study published today in the NEJM examines the risk of relapse in breast cancer patients who decide to pause endocrine therapy to try to become pregnant. The results show that temporarily stopping treatment does not confer an increased risk in the long term, but the authors warn of the need for further follow-up.
Reactions: 20-year study of the psychological well-being of children born through third-party assisted reproduction
Two decades of research has found no differences in psychological well-being and the quality of family relationships between children born through assisted reproduction with third-party intervention (gamete donation or surrogacy) and those born naturally. The results, published in Developmental Psychology, suggest that it is better to talk to them early, at preschool age, about their biological origins.
A sperm donor in the Netherlands has allegedly fathered more than 550 children in at least 13 clinics in the Netherlands and other countries. One of the mothers of these children and the Donorkind Foundation (Netherlands) have sued him. In Spain, there is a national registry of gamete and pre-embryo donors, and the law on assisted human reproduction techniques does not allow more than six babies to be born from the same donor.
Researchers in the United States have tested a new technique to select sperm and thereby increase the chances that the embryo will be of either sex. The proven efficacy is around 80 %. Although some countries such as the United States allow this type of procedure, in Spain it is prohibited except in cases of prevention of diseases linked to sex chromosomes. The authors of the article state that sperm selection is more ethically acceptable than embryo selection. The results are published in the journal PLOS ONE.
A study carried out by researchers at the University of Amsterdam Medical Centres on more than 220,000 children examines the academic performance at age 12 of children born by induced labour. According to the authors, a reduction in scores was observed in infants born after induced labour between 37 and 41 weeks. The research is published in Acta Obstetricia et Gynecologica Scandinavica.
A study in mice found that a molecule called TDI-11861 works as an oral male contraceptive, temporarily blocking sperm function. The paper, published in Nature Communications, presents the research as a step towards an on-demand male contraceptive drug: the user could take a birth control pill before sex and become fertile again the next day. Four co-authors of the study have founded a company in the US to develop such products.