Validates gender returning structured ValidationResult.
Gender value to check.
{ isValid: true, data } with 'male' or 'female', or { isValid: false, error, errors, code }.
{ isValid: true, data }
'male'
'female'
{ isValid: false, error, errors, code }
validateGender('F').isValid; // true Copy
validateGender('F').isValid; // true
Validates gender returning structured ValidationResult.