No. Not all genetic conditions are noticeable at birth.

When a person inherits a disease-associated genetic variant from either parent, that genetic change is generally present from conception. However, the presence of a genetic variant does not necessarily mean that the individual will immediately develop symptoms.

The age at which a genetic condition becomes clinically apparent is called the age of onset. Depending on the condition, symptoms may develop:
– Before birth: Some genetic conditions can affect fetal growth and development and may be detected during pregnancy.
– At birth: Certain genetic disorders present with noticeable physical features, structural abnormalities or metabolic problems.
– During childhood: Some conditions become apparent when developmental milestones are delayed or specific symptoms emerge.
– During adolescence: Hormonal changes, growth and developmental processes may reveal certain inherited conditions.
– During adulthood: Some genetic disorders remain undetected until the individual reaches their 20s, 30s, 40s or even later.

– Never: Some individuals carry a disease-associated genetic variant but never develop the associated condition because of incomplete penetrance.
For example, a person carrying a pathogenic variant associated with hereditary breast cancer may be completely healthy during childhood and adolescence but have an increased risk of developing cancer during adulthood.