Scientifically
Accurate Astrology
Your date of birth predicts your diagnoses, your schooling, and your odds of playing professional sport. Not because of Saturn. Because of school-enrolment cutoffs, gestational vitamin D, and which viruses were circulating the winter your mother was pregnant.
Enter a birthday. Every claim is cited. Nothing is stored.
YOUR ACTUAL NATAL CHART
What the date actually does
Selection effects first — the ones that are stronger, funnier, and indict institutions rather than alarm you. Disease associations are lower down, behind a click, with effect sizes and confidence intervals.
Show disease associations weaker, scarier, and easier to misread — open only with the base rates in mind
Every number below is an absolute risk shown against its base rate. A change from 0.7% to 0.8% is a change of one person in a thousand. Read it that way.
Why this works and astrology does not
Astrology and this page agree on one strange fact: your birth date carries information about your life. They disagree completely about why, and the why is the whole thing.
Astrology proposes a mechanism — the gravitational or spiritual influence of distant planets at the moment of birth — and that mechanism does not survive contact with physics. The delivering obstetrician exerts more gravitational pull on a newborn than Mars does. When astrologers' predictions are tested blind against chance, they land at chance. There is no dose, no gradient, no plausible pathway, and no replication.
The findings on this page have all four. Each has a mechanism you can point to: an arbitrary enrolment cutoff that makes one child the youngest in a room of thirty; a winter of low sunlight that lowers a pregnant woman's vitamin D; a respiratory-virus season that peaks in a particular trimester; a latitude that governs how much ultraviolet reaches the skin. Each has a dose-response gradient — effects strengthen with relative youth, with latitude, with the depth of the season. Each replicates across independent cohorts and countries. And each produces an effect small enough to be honest about and large enough to measure.
That is the difference between a horoscope and an epidemiological finding. Astrology is wrong about the mechanism and accidentally right that the date matters. This page keeps the accident and throws away the astrology.
How this was built, and where it is weak
Every finding lives in a small data object inside this page, each with an absolute-risk framing, an effect size, a sample size, a confidence label, and a link to the source. Nothing is fetched at runtime. The page talks to no server. If you think an effect size is wrong, the fix is a one-line edit and an email — corrections welcome.
The two rules we do not break
- Absolute risk, always, with the base rate beside it. "Your lifetime risk goes from roughly 0.7% to roughly 0.8%" is honest. "40% higher risk" is technically true and wildly misleading, because 40% more of a tiny number is still a tiny number. We never print a bare relative risk.
- Selection effects lead. Disease follows a click. The school-cutoff and draft findings are stronger evidence and they indict institutions, not individuals. Disease associations are smaller, easier to misread, and sit behind a click with their confidence intervals visible.
What is genuinely weak here
- Personalisation is approximate. School-enrolment cutoffs vary by state, province and year. The ones offered here are representative, not authoritative. Sports selection years differ by sport. We tell you where your birthday probably sat. We cannot know where it actually sat.
- Season-of-birth disease effects are small and partly contested. Some have been argued to be statistical artefacts of how birth dates cluster. We label those Mixed or Contested rather than hiding them.
- Confounding is everywhere. Birth timing is not random — season of conception correlates with parental income, planning, and geography, any of which could drive an association attributed to the calendar.
- Absolute risks are population figures. They shift the average across a cohort. They are not a forecast for you, and they are not diagnostic.
Sources
The print
The web toy is free and forgets you. The object does not: a letterpressed natal chart cast from your date, with every citation printed on the reverse, in an edition. We call it a chart and let the double meaning sit there. Enquire through POLYGENIK.