Editorial Policy & Disclaimer

Editorial policy

We distinguish documented calendar history and identifiable research from folklore, estimates, and uncertain origin stories.

Calendar data.

Date calculations use lunar-javascript with generated overrides from Hong Kong Observatory Gregorian–Lunar Calendar Conversion Tables. Official table coverage is 1901–2100; dates outside that coverage are not described as HKO-verified. The browser uses bundled data and does not call an HKO API.

Hong Kong Observatory conversion tables · DATA.GOV.HK dataset

HKO notes that calendar calculations for distant dates may be uncertain. We preserve that qualification rather than suggesting that far-future astronomical or civil dates are beyond revision.

Chart and worked examples.

The calculator and visible chart use the same 28-row, 12-column table. Leap months are assigned to the same numbered column as the regular month they repeat, and this convention is disclosed wherever relevant. Worked examples are checked against the implemented date functions before publication.

Historical and cultural claims.

We distinguish documented calendar history from stories about the chart’s invention or discovery. Uncertain origin accounts are labeled legends or folklore. We do not invent an author, medical reviewer, expert credential, primary manuscript, or “original” source.

Scientific and medical claims.

Accuracy statements rely on identifiable research, principally the 2010 population-based study indexed as PubMed 20618730. General prenatal-screening context is checked against patient guidance from the American College of Obstetricians and Gynecologists. We do not turn testimonials into success rates or present screening as diagnosis. Content does not replace individualized advice from a qualified healthcare professional.

Folklore & medical disclaimer

The Chinese Gender Calendar is a traditional folklore method with no scientific or medical basis. A Boy or Girl output is only the label stored at an age-and-month intersection in that chart.

It is not a diagnosis, medical screening result, or reliable prediction of a baby’s biological sex. Research has found the method performs no better than chance. See our accuracy review.

No medical advice.

This website provides general cultural and calendar information. It does not provide medical advice, prenatal care, fertility guidance, or gender-selection services. Do not use it to make medical, reproductive, financial, or other important decisions.

Consult a qualified healthcare professional about pregnancy dating, ovulation, IVF, prenatal screening, ultrasound, diagnostic testing, or any question about fetal sex. Medical methods have their own purposes and limitations that a professional can explain.

Estimated dates and chart conventions.

Adding 14 days to an LMP date and subtracting 266 days from a due date are approximations. Actual conception may occur on a different day. Using an embryo transfer date is a declared chart convention, not a statement that transfer and fertilization are identical.

Different chart versions and leap-month rules exist. We publish our table and use the same numbered column for a leap month and the regular month it repeats. A calculation can faithfully reproduce our chart without having predictive validity.

No guarantees.

We aim for consistent calendar calculations and clear educational content but do not guarantee that every page will always be uninterrupted or free of error. Calendar sources also qualify distant-date certainty. By using the site, you accept responsibility for how you interpret and use its folklore outputs.

Automation and corrections.

Automation may assist with drafting, code, and date validation. It does not establish authority by itself; important claims should be traceable to the sources shown on the page. Pages are updated when calculations, sources, or site behavior change.

Correction reports should include the page URL, relevant dates, observed result, and supporting source. See the contact page.