Thereasonsforsuchchangesarecomplex.Someproponentsofequalityforsexualminoritiescontestthatitisevennecessarytoexplainandjustifythedevelopments.Theyassertthat，inprinciple，itisnobusinessoftheStateorthecommunitytodiscriminateamongstcitizensinbasiccivilrightsonthefootingofwhatthosecitizensdosexuallyintheirrelationswithotheradultsorinthebondsthattheyformwithotherhumanbeings.Forthem，theseareprivatematters.Theorganisedcommunityhasnorighttointerfere.Ithasadutytotreatallpersonswithequalitybecausethatisafeatureinherentinthehumandignityofallofus.
Giventhatinmany（perhapsmost）countriesoftheworldlaws，religion，socialstigmaandotherimpedimentsstillexisttotrueopennessaboutsexualorientation，outsidethemajoritynorm，thewidespreadchangesthathaveoccurredinthepastfewdecadesareremarkable.Itisworthcollectingsomeofthecauses.Theyinclude：
（1）Theadvanceofunderstandingofhumanpsychologyandtheresearchperformedduringthetwentiethcenturyintofeaturesofsexualattraction.ThewritingsofSigmundFreud，AlfredKinsey，EvelynHookerandothershelpedtodemonstrate，empirically，thevarietyofsexualexpressionamongsthumanbeingsandtheimperfectionsofthestrictbinaryassumptionuponwhichearliermoralattitudes，inpartatleast，hadrested；