Sourcing standards
- A claim and its source travel together. Any statement about what affects sperm, by how much, or how quickly, is followed by a linked source: a DOI for a paper, or a page from the WHO, the NHS, ASRM, ESHRE, NICE or a comparable body. A claim with no source does not ship.
- Strength of evidence, in order. Systematic reviews and meta-analyses first; then committee opinions and clinical guidelines; then large cohort or cross-sectional studies; then small or single studies, which are named as such. Animal studies and mechanistic reasoning can explain a finding but never stand in for one in humans.
- Numbers are quoted, not rounded up. Effect sizes and timeframes are the ones the source reports, with the population it studied. "Around 29% lower in the most disturbed sleepers" is a fact from one study; "sleep improves sperm by 29%" is not, and it will not appear here.
- Primary over secondary. Press releases, product pages, blog posts and other apps are not sources for health claims. They may be cited for what a product says about itself.
- Sources are checked, not copied. Each source is opened and read before it is cited. A citation that cannot be opened, or that does not say what the sentence says, is removed with the sentence.
WHO 2021 as the semen reference
Wherever this site or the app shows a semen analysis number against a limit, the limit comes from the WHO laboratory manual for the examination and processing of human semen, 6th edition (2021): the 5th centile lower reference limits, drawn from men whose partners conceived within 12 months. Volume 1.4 mL, concentration 16 million per mL, total count 39 million, total motility 42%, progressive motility 30%, vitality 54%, normal morphology 4%.
Three things are always said alongside those numbers. They are reference limits, not a line between fertile and infertile. Results vary between samples from the same man, which is why clinics repeat the test. And interpreting a result is a clinician's job. If a newer WHO edition is published, the site and the app move to it together, and the pages that quote the limits say which edition they use.
Hedging rules
Most research on lifestyle and sperm is observational: it shows association, not cause. The language on this site is chosen to match that.
- "Is linked to" and "is associated with" for observational findings. "May" and "can" for plausible but unproven effects.
- "Improves" or "reduces" only when a randomized trial or a meta-analysis of trials supports it, and then with the size of the effect.
- Where studies disagree, the disagreement is stated, not resolved by picking a side. "The evidence is mixed" is a legitimate sentence here.
- Where the evidence rests on general guidance rather than fertility-specific research (hydration is the usual example), the copy says so.
- No manufactured precision: round, real numbers only, never a decimal the data does not justify.
No diagnosis, no promises
Motily is a lifestyle and wellbeing tool, not a medical device. Nothing on this site or in the app diagnoses a condition, tells you that you are or are not fertile, or promises that a change will lead to a pregnancy. Tools on this site that show your numbers against reference limits do exactly that and no more, and they tell you to discuss the result with your doctor.
Every page that discusses health tells you when to see a doctor: after a year of trying without success, or six months if your partner is 35 or older, and sooner if you have a known risk such as a varicocele, an undescended testicle, past chemotherapy, or testosterone or steroid use. Seeing a specialist is framed as a normal, proactive step, never as a sign something is wrong.
Update cadence
- Quarterly review. Every guide, the science page and the FAQ are re-read against their sources at least every three months. New meta-analyses or guideline changes are folded in at that point, or sooner when they change a recommendation.
- Dated pages. The "Updated" date on a page changes when its content changes, not on every deploy. If a page's date is more than six months old, it is overdue and you are welcome to say so.
- One fact, one place. Numbers that appear in several places (WHO limits, the score weights, prices, the phase lengths of the 74-day cycle) come from the app's own code, so the site and the app cannot drift apart.
How to report an error
Email [email protected] with "Correction" in the subject, the page address, and what you think is wrong. If you have a source, include it. Reports are read by the person who wrote the page, usually within a few days.
A confirmed factual error is fixed on the page, the page's update date changes, and if the error was material (a wrong number, a claim the source does not support) a short note at the bottom of the page says what changed. Nothing is quietly rewritten.
Independence and disclosure
Motily makes the Motily app. Any page on this site that compares apps, at-home tests or products says so at the top, is written to be fair and specific about the alternatives, and links to the sources it used. There are no affiliate links, no sponsored content and no paid placements on this site. If that ever changes, this policy changes first and the affected pages are labeled.