In a question of mine somebody commented that it is better to split this post into three different questions. Is it a good idea or the current format is fine? I think all questions are somehow related to the title of the post namely the situation of LGBT people in mathematics. However I'm not sure.
This site, and the SE format in general, works best for quite focused questions. In particular, ideally, a question-post should admit an in some sense complete answer in a couple of paragraphs. In particular, questions that are "too broad" can be closed for this reason.
As a consequences it is best not to ask different questions that are only related by being on a common subject in one post. (Especially not when even individually they are somewhat broad already.) In general, it is good to strive for "one question per post." Of course, this is not to be taken as strict rule and questions where really one depends on the other, can be asked in one post.
For your specific question, I agree with the comments that the three sub-parts would be better not in one question.
Furthermore, the second part seems not very specific to mathematics education; especially, the part on tenure is more a general question about academic institutions. Similarly, the third point in its current form is also not a question about mathematics education, but rather personal/biographical information on mathematicians.
Thus, for now I would propose to edit the question to focus on the first part only. The other questions would need some revision and precision before making on-topic question on this site.
I agree that the first question in the most important and that it definitely does need to be split into 3 different questions. That being said, I have a number of reservations about the way you have worded the first question that I have detailed below.
I believe that a student's experiences and culture are a vital aspect of why they are or are not successful in a math classroom. It is easy to dismiss such concerns on the grounds that math is "objective". One, therefore, does not have to worry about choosing literature sensitive to a certain group of people or which emphasizes their history. However, the math classroom does occupy significant cultural territory. While the content may not be a cultural issue, the environment certainly is and the environment is a direct product of pedagogy. Hence, my argument that this is in fact a relevant question to this forum. Nonetheless, I do not believe that this question properly poses this problem.
As an LGBT educator, I find the word "ordinary" to as used to describe non-LGBT people as the kind of language, as Xi Yu refers to in her comment on the original post, that marginalizes the experience of LGBT students and reinforces their sense of "otherness". Secondly, the question focuses on the issue of aptitude rather than attitude according to the your use of the phrase "better or worse" and the phrase "ability". While this question has been tagged "cultural difference" I would like to point out that you don't actually use the world "culture" anywhere in the question. Your attempt to draw a connection to another biological feature, handedness, seems to suggest that your are mostly interested in whether biological differences causes differences in achievement. There is a long history of such studies involving race. We currently understand that the racial achievement gap as well as the gender achievement gap in STEM fields is a product of culture -- not biology. Fortunately culture is far more malleable than biology and is something that pedagogy can accommodate.
For instance, it is suggested in some research that some LGBT students have an "overachiever complex" where they compensate for their sense of inferiority related to their sexual orientation by attempting to be successful elsewhere in their lives. On the other hand, the bullying that is commonplace to LGBT youth might make the risk taking that is often involved in a math classroom that much more scary. Robert Moses writes in The Algebra Project about the need to transform math pedagogy to meet the needs of African American youth by responding to their cultural environment and such concerns are true for any minority.
Relevant questions might be "How do the unique experience of LGBT students impact their ability to succeed in a math classroom? What pedagogical approaches are necessary to be inclusive and sensitive to this experience?" Or perhaps a more general question "How doe the unique experiences of minority students impact their ability to success in a math classroom?"