X-Linked Recessive Inheritance 2D Simulator

Parents

Father

Mother

Simulated children40

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Theoretical odds

Outcome		Theory	Simulated

Chromosome key

Normal allele (Xᴬ) Disease allele (Xᵃ)

How it works

Each simulated child gets a random gamete from each parent: the father passes his X (50%, makes a daughter) or his Y (50%, makes a son); the mother always passes one of her two X copies, chosen with 50/50 odds each time. A son's single X is expressed directly — no second copy to mask it. A daughter needs the disease allele on both her X's to be affected; one copy makes her an unaffected carrier.

This is a Monte-Carlo demonstration of the Law of Large Numbers: with a small family the observed percentages jump around, but as "Simulated children" grows toward 200 they settle closer to the exact theoretical fractions shown in the table on the left.

Unaffected Carrier Affected

X-Linked Recessive Inheritance — 2D Monte Carlo Simulator