I don't know about 'a few specific cases'. STIs, mental health issues, pregnancies (interrupted or not, voluntarily or not), contraception methods and/or lapses, anything often misunderstood like MS or neurodegenerative diseases, huntington, substance use/abuse (voluntary or not), victim of assault (sexual or not), sterility/fertility/impotency/incontinence, any manageable medical issue someone might use to not give you a job, to rent you an apartment, although you do actually manage it well...

None of those I'd want shared anywhere, to anyone, against my will. Those (overall) are not rare.