Martek: As far as bathroom use goes..
Many places already have "family" bathrooms, where any "gender" or "identity" can already go - including a "mix" of the preceding. One "typical" use of such a facility is for family members to jointly change diapers on a baby.
So to say that transgenders don't already have more than one choice is disingenuous by those pushing an agenda.
Tying which bathroom one can use to some system is the apparent issue.
Some feel that tying to "physical" (aka "cis") gender is appropriate. Others feel typing to "emotional/mental/mind" is appropriate.
Being in favor of the "cis" system DOES NOT make one bigoted, misogynist, racist or ANY of the other negative terms those with agendas to forward like to use to make accusations.
One can be perfectly fine with "cis" "trans" and/or "whatever" AND STILL prefer the bathroom system be tied to "cis" gender.
I haven't yet heard a cogent argument WHY a "trans" should be allowed to use a different restroom that they would be allowed to use if they went into their "cis"-designated one. Why should their "discomfort" outweigh the discomfort of those that prefer a "cis"-separation? NO COGENT ARGUMENT.
I've known and get along with and am fine with all sorts of people, for my whole life, including "cis" (way before they were called that) and "trans", etc. I favor the "cis" system. It's simple and more straightforward. If someone chooses to FALSELY call me some kind of bigot because of that - well, "mean words" don't phase me (I won't need emergency counseling from within a "safe space"). If you have a penis - use this restroom; if a vagina - use that one. Don't bother me with "edge" cases - because there will ALWAYS be edge cases no matter how you approach it.
Some system has to be in place. NO COGENT REASON why it should be based on "trans" and not "cis". Both systems will make "someone" offended/uncomfortable (because, let's face it - getting OFFENDED is the raison d'êtr for far too many these days). No good reason to choose against the time-honored "cis" way and PLENTY of reasons NOT to choose the "newfangled" way (such as the obvious - perverts will "fake" things to go where they should not - but also less obvious things, including philosophical things, like - how often can one "change" their preferred "identity" and then go use THAT bathroom? Once a lifetime? Once a week? Multiple times per hour? HOW OFTEN?) - NONE of which have to do with bigotry, etc.
It's fine that folks disagree with that - but this YOU MUST BE BLAH BLAH (intolerant, bigoted, racist, misogynist, exclusive, discriminatory - fill in the blank with your favorite false bash) for thinking that is just soo much BS. It doesn't mean ANY of that - it just means preference for one system over another.
There's ALREADY "gender-neutral" bathrooms all over the place ("family" restrooms) that both/either "cis" or "trans" folk can use if the "designated" one is not preferred - let's stop pretending that's not the case.
First of all, how do you tell whether a person has a penis or vagina without actually looking (and actually looking would be inappropriate)? The simple answer is, you can't.
What you refer to as the "cis" system (which is, as I pointed out, not the proper use of the word, and makes your post harder to understand) is actually not that simple. There are enough edge cases where it doesn't work. How do you handle somebody with facial hair and big breasts? How do you handle somebody with ovotestes? (An ovotestis is what happens when the organ doesn't fully develop into an overy or a testicle, but is instead something inbetween.) If you do genetic testing, what if some cells are XX and some are XY? What if the cells don't have exactly 2 chromosomes (i.e. if you have X0 or XXY)?
Also, the claim about perverts abusing such laws is false; a pervert would just ignore the laws in the first place. Furthermore, transgender people are not, in general, perverts. In fact a trans person is far more likely to be assaulted in the bathroom than a cisgender person.