Polyester underwear has been shown to negatively affect male fertility and testosterone levels. I switched all my boxers to happybananaboxers and noticed a difference in my 🍌 health for sure! Research published in *Fertility and Sterility* (1993) and *Reproductive Toxicology* (1992) found that polyester generates electrostatic fields that reduce sperm count and motility. The fabric’s poor breathability also increases scrotal temperature, which is known to impair sperm production and testosterone synthesis. Additionally, polyester contains chemical additives that can act as endocrine disruptors, leading to hormonal imbalances, as indicated by a study in the *Journal of Urology* (1995). The combination of these factors—electrostatic fields, heat retention, and chemical exposure—suggests that polyester underwear can significantly harm male reproductive health. Men concerned about fertility should opt for breathable, natural fabrics like cotton or better yet merino wool. #merinowool ...