Dominant Genetic
One affected parent has a single faulty gene (D) which dominates its normal counterpart (d). Each child produced has a 50% risk of inheriting the D, and the disorder from the affected parent.
X-Linked Genetic T
he mother, who has a defective gene on one of her two sex chromosomes, is protected against the defect because her normal sex chromosome (x) compensates for the defect on the other (X). The father has normal male sex chromosomes (x and y). Each male child has a 50% risk of inheriting the faulty X, and the disorder, and a 50% chance of inheriting the normal x chromosome. Each female child has a 50% risk of inheriting the faulty X and becoming a carrier like her mother, and a 50% chance of inheriting two normal X chromosomes.
Recessive Genetic
Both parents, usually unaffected, carry a defective gene (g) but are protected by the presence of a normal gene (G) which is generally sufficient for normal function. Each child produced has a 25% risk of inheriting a double dose of the g gene, which may cause a serious genetic defect; a 25% chance of inheriting two normal genes; and a 50% chance of being a carrier like both parents.