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TSH is not part of the reproductive system, but an underactive or overactive thyroid has been linked to lower testosterone, worse sperm quality, and elevated prolactin. Here is what a high or low TSH result actually means for male fertility, and when it is worth testing.
Testosterone therapy can shut down sperm production almost entirely, and most men are never told to get a baseline semen analysis and hormone panel before starting. Here is exactly what to test first, and why the guidelines already say so.
Total motile sperm count, or TMSC, predicts IUI and IVF outcomes better than any single semen parameter alone. Here is what the research actually shows, and where SwimScore is more skeptical than the marketing around it.
A normal semen analysis is real good news, but it was never designed to check for everything. Here is what concentration, motility, and morphology do not measure, and what is worth testing next if you are still not conceiving.
A low sperm concentration with normal motility is a specific, less common pattern with its own set of causes. Here is what the research actually shows, and what is worth checking before assuming the worst.
A controlled sleep lab study shows testosterone drops within days of short sleep, and large population studies link disrupted sleep to worse sperm quality. Here is what the research actually supports, and where the evidence on sleep apnea and testosterone gets more complicated than the headlines suggest.
Excess body fat converts testosterone into estrogen through an enzyme called aromatase, which suppresses the hormones that drive sperm production. Here is what the research actually shows about obesity, weight loss, and sperm quality, and where the evidence is more mixed than it first appears.
If your testosterone is low, the standard fix is testosterone itself, and it can quietly shut down your fertility. Enclomiphene raises testosterone by a different route, one that keeps sperm production running. Here is how it works, what the research shows, and who it actually helps.
Laptops, saunas, hot tubs, and tight underwear all raise scrotal temperature, and heat measurably changes sperm production. Here is what the actual research says about which habits matter most, and which ones are probably not worth panicking over.
A varicocele is the most common correctable cause of male infertility, yet most men have never heard of it. Here is what it is in plain English, how it affects sperm, what the research says repair can and cannot do, and who actually benefits.
The headlines have been running for years. Sperm counts are collapsing. Men are becoming infertile. The human species is in reproductive crisis. RFK Jr. cited it in speeches. Scientists have written open letters to governments about it. The 2017 meta-analysis that started the modern conversation has been cited thousands of times.
The reality, as of 2026, is more complicated than the headlines suggest — and more useful for any man who actually wants to understand what the research says about his own fertility.
This is what the science shows, where the genuine uncertainties are, and why the question of what is happening to sperm counts globally is separate from the question of what is happening to yours specifically.
Alcohol is probably the lifestyle factor men are most curious about and least honest with themselves about. The question isn't whether drinking is enjoyable. It's what it's actually doing to your testosterone, your hormones, and your sperm, and at what point the amount you're drinking starts to matter.
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