The introduction of the female contraceptive pill in the 1960s marked a significant change in sexuality and family planning. According to Marta Correa, a doctor at the Assisted Reproduction Unit of the University Hospital of the Canary Islands (HUC) and member of the Spanish Society of Contraception (SEC), the future development of a male contraceptive pill will represent another major advance.
Currently, male contraception options include condoms, which also protect against sexually transmitted diseases, and vasectomy, a surgery that cuts the vas deferens to prevent sperm from reaching the urethra. This surgery is permanent.
**Reversible Vasectomy Under Study**
Research into reversible vasectomy has been carried out, with advanced clinical trials in countries such as India, Australia and the United States. These studies explore the possibility of using injections of silicone and polyurethane polymers into the vas deferens to allow men to regain fertility after the material has been reabsorbed. However, many of these studies were abandoned because reversibility could not be demonstrated in all cases after one year, despite being in advanced stages.
**New Research**
There are other non-hormonal methods under investigation that seek to address male contraception in a variety of ways, from inhibiting sperm motility to interfering with fertilization and spermatogenesis. Some approaches are promising, although they have not yet reached the clinical phase and have been tested mainly in mice.
A team at Baylor College of Medicine has investigated the inhibition of serine/threonine kinase 33 (STK33), a protein crucial for fertility in men and mice. Deleting STK33 in mice causes sterility by producing defective sperm. Although these results are encouraging, these findings still need to be validated in humans.
**Research on Hormonal Contraception**
In the field of male hormonal contraception, daily combinations of testosterone gel and nestorone are being evaluated to suppress sperm production. Studies have shown that this combination can reduce sperm production to undetectable levels in 90% of cases over a period ranging from 20 days to 20 weeks. Research continues to understand the duration and efficacy of this method and to address cases where azoospermia, defined as less than one million sperm per milliliter, is not achieved.
On June 4, American scientists presented advances in this area, which are in phase 2b of research, evaluating the effectiveness of the new male contraceptive method.
