Why are 'Age or age at death' and 'Year of birth' vital to risk estimates?

When calculating risks, the CanRisk Tool considers information on disease status (affected/unaffected and age) only for family members with a valid 'Age or age at death' and 'Year of birth'. If either of these parameters is unspecified, only that person’s genetic testing information (if available) and family relationship will be taken into account in the risk calculation. As a result, these parameters are vital to CanRisk Tool risk estimates.