This page outlines some of the standard questions used for gender identity and sexual orientation. For gender questions please see the separate entry: STANDARD QUESTIONS – gender.
The Writing Themselves In project (2010 survey of over 3,000 SSAGQ 14-21 year olds across Australia – 3rd in a series – 1998, 20014, 2010 – link) uses the following questions. 1C and 2E are fairly standard, although you probably don’t need both 2A and 2E as they provide the same information (2E is just the ‘label’).
2A would probably be better for young people, although, it would benefit from a code saying ‘I haven’t really thought about it yet’ so that option 4 is the questioning one:
1C. Are you?
1. Male
2. Female
3. Transgender m-f
4. Transgender f-m
5. Gender Queer
6. Other
2A. Which one of these statements best describes your sexual feelings at the moment?
1. I am attracted only to people of my own sex
2. I am attracted to people of both sexes
3. I am attracted only to people of the opposite sex
4. I am not sure to whom I am attracted
2E. Do you think of yourself as:
1. Gay, homosexual, lesbian?
2. Bisexual?
3. Heterosexual (straight)?
4. Queer?
5. Questioning?
6. Other
The Williams Institute suggests the following as a standard question (link):
1. People are different in their sexual attraction to other people. Which best describes your feelings? Are you:
a) Only attracted to females?
b) Mostly attracted to females?
c) Equally attracted to females and males?
d) Mostly attracted to males?
e) Only attracted to males?
f) Not sure?
A YAcVic / Australian Human Rights Commission survey (link) asks the following:
1. How would you describe your sexual orientation? (choose as many options as you like)
- gay
- lesbian
- same sex attracted
- bi sexual
- hetrosexual (straight)
- homosexual
- pansexual
- queer
- Other (specify)
2. How would you describe your gender identity? (choose as many options as you like)
- male
- female
- transgender (male to female)
- transgender (female to male)
- gender questioning
- pansexual
- queer
- Other (specify)
A survey found on reddit used the following series, providing greater insight (the survey is no longer available and was not linked to any larger scale study or organisation):
What is your sexual orientation? (Who are you sexually attracted (desire sex with) to?)
1) Heterosexual (people of the opposite sex/gender)
2) Homosexual (people of the same sex/gender)
3) Bisexual (people of the same and different sexes/genders)
4) Polysexual (people of some, but not all, sexes and genders)
5) Pansexual (people of all sexes and genders)
6) Asexual (no one)
7) Demisexual (people, after an emotional connection has been made)
8) Other Ace-Spectrum Sexuality (non-listed sexuality that leans towards asexual)
9) Other Non-Ace-Spectrum Sexuality (non-listed sexuality than leans away from asexual)
10) I don’t know/am not sure yet
What is your sex? (Your physical self)
1) Male
2) Female
3) Intersex
4) In Transition
5) I don’t know
What is your gender? (Your psychological self)
1) Male
2) Female
3) Amalgagender (gender for intersex)
4) Gender-Fluid (felling of being different genders over time)
5) Agender (feeling of no gender)
6) Androgynous (feeling of both male and female genders)
7) Other Non-Binary (gender not included above)
8) I don’t know/am not sure yet
What is your romantic orientation? (Who you are romantically attracted (desire dating/romance with) to?
1) Heteromantic (people of the opposite gender/sex)
2) Homoromantic (people of the same gender/sex)
3) Biromantic (people of the opposite and same genders/sexes)
4) Polyromantic (people of some, but not all, genders and sexes)
5) Panromantic (people of all genders and sexes)
6) Aromantic (no one)
7) Demiromantic (people, after an emotional connection has been made)
8) Other Aro-Spectrum Sexuality (non-listed sexuality that leans towards aromantic)
9) Other Non-Aro-Spectrum Sexuality (non-listed sexuality that leans away from aromantic)
10) I don’t know/am not sure yet
In conclusion/TLDR;
You probably just need 2 questions; 1 with an extended gender list and 1 to ascertain sexual orientation. For sexual orientation Q2A from the Writing Themselves In 3 survey (with the suggested tweak) would probably work better with young people, however the standard label list would offer more opportunities for comparison to other research.
Another reference: collecting transgender inclusive gender data in workplace and other surveys
Further reading: Measuring Sexual Orientation Identity and Gender Identity in a Self-Administered Survey: Results from Cognitive Research with Older Adults