This myth is false.
Reference letters must not be provided by family members, family friends, colleagues of family members, neighbours or someone who may be perceived as your peer, as we do not consider them to be objective. Even if one of these individuals has supervised you in a work, volunteer or academic setting, there is a perceived bias given this close relation to you. Instead you should select referees who can be objective about your performance, abilities and attributes.
Applications from candidates with non-objective reference letters will not be considered.