Mentioning LGBTQ Identity in Personal Statement for PhD Applications

Edit (in response to revised question):

In light of the revised question, this sounds like exactly the sort of thing they are asking for, so yes feel free to talk about L, G, B, T, Q and X. However, my guess is that whatever you write here won't make too much of a difference (as long as you don't make yourself sound crazy or anything), for the same reasons I indicated in my original answer.

Original Answer Below (where it sounded like this was about a personal statement):

Unless they are asking specifically for you to address diversity issues, I don't think it matters much what you say about LGBTQ issues in your personal statement, as it has nothing to do with physics. Note: depending on the department and admissions committee, the statement of purpose may be important or not important (e.g., Why do admissions committees consider the Statement of Purpose to be important? and How important is the statement of purpose in a PhD application for admission to a top school in the US?).

What I look for in a statement of purpose (in math, which I imagine is similar to physics) is basically what I look for in the rest of the application: your preparation for grad school, your talent and work ethic, your interests/fit with our program. Though it also helps to get a sense of your personality (so it's not good, e.g., if you sound like a crackpot).

I don't think the issues mentioned in your question reflect too much on these things. On the other hand, I don't think it will hurt your application if you want to briefly mention at least (1) and possibly (2) if you can weave them in naturally, but these things shouldn't be the focus of your personal statement, as they say nothing about why you want to go to grad school. (Certainly your CV is a suitable place for (1), so it can make it onto your application there.) Academia is relatively LGBTQ friendly in my experience. However, we don't want to know your whole life story on your application, just the part of your story related to (in your case) Physics.

I am scared that I will be risking my chances of getting into grad school by mentioning what's still considered a very 'controversial' issue by many people.

There's never any need to hide a personal commitment to diversity in an application in the U.S. In other words, it would always be appropriate to list your specifics in sections on volunteer or leadership activities. Also, if you received recognition or an award in connection with diversity advocacy or activism, definitely list it. The admissions committee might include someone with a strong personal commitment to diversity, and if your application contains a clear hint that would make the diversity bell in that person's mind go "ding ding ding!", s/he can then push to get you on the short list.

However, I do understand your feeling of uncertainty about putting your commitment front and center. Researching each specific university you're applying to will help you tailor the application to the position.

For some applications, you can write exactly what you wrote in your question (including the relevant details, within the space constraints, of course). If a university specifically requests a diversity statement, that is a helpful clue that they may be looking for someone who will provide the kind of leadership you are hoping to provide. Some universities are desperately trying to find people who will be an asset academically, while also strongly supporting diversity so they can increase their diversity graduation statistics.

At the other end of the spectrum, let's say there are no indications on the website of a strong commitment to diversity. Maybe it's a small school with low diversity in its student body. In this case you might choose to leave this aspect of yourself more in the background. Quietly discernable.

Bonus feedback: If I were on the admissions committee, reading what you've written here, I'd say it's a great start for a diversity statement. But I'd also be looking for someone who can generalize from his or her specific experiences. Can you expand your statement a bit, building on your own experience, to arrive at a supportive stance towards other types of diversity as well? For example, if you've ever been involved in allying with other types of campus diversity organizations, that would be helpful to include in your essay.

I can speak from personal experience in this arena.

I was out in my Diversity Statement to UC schools and any other school that asked about, but not in any Statement of Purpose or Personal History. I suggest just reading everything very carefully. Oftentimes, the groups that they state as ones that they do not discriminate will be different from the ones they count as diversity. There's a stock term of "visible minority" that is used to discount LGBT people as diversity. I don't suggest pushing against this. If they do that, then the university administration is not ready. Even if the department want to do something with this, they cannot. If they say something relative to LGBTQ stuff, then have at it (it's my impression that most if not all of the UC system is happy with work for LGBTQ folk counting). If they do not specify, go for it.

My understanding is that, typically, the diversity statement will only factor in after they already know they want to accept you for purely scientific reasons. For example, I think UCSD can use this to find new fellowships through the administration.

An important thing to note is that (for the UC system) often they want to see that you have done something with respect to underrepresented groups, not just are a part of one. If being a part of one helps the author understand your motivation, then feel free to throw that into the diversity statement.

If accepted, you should be ready to walk into that department with everyone knowing. I declined going to a university after being accepted where I was out on my grad school application. At prospective weekend, the grad chair was very keen and quick with correct pronouns for my partner. YMMV. Also, people do not forget. I then met a faculty member again five years later after the prospective weekend and remembered what I had said in my diversity statement.