Many people (mostly women) do not wish to reveal their "number". Not wanting to be "slut shamed", "the past is the past" and an overall fear of losing out on an LTR seem to be the major motivating factors for not wanting to disclose. However, since your risk for contracting STDs goes up with the more partners you had, is an up to date and accurate count not a reasonable request from a potential suitor? Yes, you can say it doesn't matter as long as you test out fine, however:

  1. There are strains of HPV that cannot be tested for.

  2. There are windows where virus' can reside in you without enough time passing to allow for accurate testing to take place.

  3. If you won't reveal something as basic as your partner count, why should you be trusted to reveal accurate STD test results?

Ideally, we need real time, on the fly testing but this is many years away (not counting the delays from all the groups protesting such a system); however, until we have all that, is requesting as much information as possible before risking your own health, unreasonable? Are physical health concerns more important than peoples "feelings"?