About GeneKids

What GeneKids is

GeneKids is an independent project created and maintained by LianaWebs. It offers three free family calculators: a statistical adult height prediction with growth percentiles, a simplified model of eye and hair color probabilities, and a calculator of biologically possible blood type combinations.

The idea came from a simple observation: when parents search online for "how tall will my child be?" or "what eye color will my baby have?", they almost always find either calculators that spit out an exact number with no explanation, or articles that never answer the question. Something in between was missing: a tool that gives the number, but also honestly explains what it means and what it doesn't.

Where the data comes from

All three calculators use public, documented methods — no proprietary or "secret" algorithms:

Height: we use the mid-parental height formula, the standard method in pediatric practice, together with growth reference tables based on WHO standards. The ±8.5 cm range we show reflects the real variability documented in the literature, not an invented margin.

Eye and hair color: we use a simplified popular-science model based on observed frequencies for each parent combination. We label it clearly as approximate, because these traits depend on more than a dozen genes and no simple model predicts them accurately.

Blood type: here there's no approximation: we apply the Mendelian inheritance rules of the ABO system and Rh factor directly. Which types are possible or impossible is established genetics, not an estimate.

What this site is NOT

We're explicit about this because we consider it more important than traffic: GeneKids is not a medical or diagnostic tool. It doesn't replace a pediatrician's assessment, it doesn't substitute for clinical genetic analysis, and it cannot be used as a paternity test.

On blood type in particular: it can rule out a paternity in genetically impossible combinations, but it can never confirm one. Any site suggesting otherwise is misinforming you. For a real answer, the only valid test is a DNA test at a certified laboratory.

Privacy: why nothing is sent to a server

All calculators run entirely in the user's browser. The data typed in — the parents' heights, the child's age, the blood types — is never sent to any server, never stored, and never shared. When you close the tab, it's gone.

This is a deliberate decision. This is information about children and families, and the safest way to protect that data is simply not to collect it.

How the site is funded

GeneKids is free and will stay that way. The PDF reports cost nothing and no features are locked behind a payment.

The site is supported by advertising and voluntary donations from people who find it useful. Donations grant no extra access: those who donate and those who don't receive exactly the same. If you'd like to support the project, you can do so on Ko-fi or PayPal.

Corrections and contact

If you find an error in any data, a calculation that doesn't add up, or wording you consider misleading, we want to know: write to lianawebs8@gmail.com. Fixing a content error takes priority over everything else in this project.