Genetic conditions are diseases that can be passed from parents to children. Some conditions may be inherited if only one parent has the changed gene, while others can be inherited only if both parents have the changed gene.

If one or both parents have a gene change (mutation) or have a genetic condition, the risk of passing the condition on to a child is the same with each pregnancy. Having one healthy or one affected child doesn't change the odds that future children will or will not be affected.

If the baby's mother or father or anyone in either of their families has a genetic condition, genetic counselling may help the family decide what type of prenatal testing they want.

Genetic conditions that may be inherited include:

• Cystic fibrosis.
• Duchenne muscular dystrophy.
• Fragile X syndrome.
• Hemophilia.
• Huntington disease.
• Polycystic kidney disease.
• Sickle cell disease.
• Tay-Sachs disease.
• Thalassemia.

A small number of conditions occur because of a one-time mistake in a single gene (new mutation), such as a change in a gene of one of the parents' egg or sperm cells or because of a change in a gene of the fetus. These one-time genetic changes are unlikely to happen again in future pregnancies.