A Guide to Litigating Identity Systems gathering and exhibiting data without a legitimate, proportionate and necessary purpose.”325 77. Due to the near impossibility of subsequently altering biometric data recorded during the data collection phase of identity systems, it is important to ensure that other data like recorded sex can nevertheless be altered afterwards so that trans persons are not deprived of their basic rights. As the Independent Expert notes, the question of when information on sex is necessary to collect in the first place is also at issue. 325 UN General Assembly, A/73/152 at 12. 76