Homosexual (or homosexuality)
What's wrong with it: In the DSM-II, the word "homosexuality" was used in a diagnostic way; it was removed in 1973. Today most psychologists believe sexual orientation has a strong genetic basis that one cannot and should not try to alter.
Preferred terms: Gay (or gay male), lesbian, and bisexual, are all considered appropriate terms. Psychologists sometimes abbreviate this as GLB or GLBQ in speech and writing. The Q refers to the queer subculture, though if you're not part of it, your best bet is to stick with "gay," "lesbian," and "bisexual" unless you're specifically asked to use the q word.
People often feel strongly about which term they prefer, so it's best not to assume someone considers himself gay just because he has a male partner right now. He may consider himself bisexual, undecided, or straight but with a same-sex partner. Some people refuse to label themselves and call themselves [current-partner's-name]-sexual. It's okay to ask someone you have a good, respectful relationship with how s/he identifies so you can be sensitive to that identification.
Stereotypes about sexual orientation are still strong in our culture, and most people don't realize when their language is biased. Psychologists should always be careful to avoid bias in their language. Though it can sound like a mouthful to always say "significant other" rather than specifying "boyfriend" or "girlfriend," it becomes habitual after you've been doing it for a while.
Other terms that your psychologist would use:
- Significant other or partner instead of assuming the person has a male-female relationship by using husband or boyfriend to a woman or wife or girlfriend to a man. This becomes a standard part of any culturally-sensitive psychologist's vocabulary, so it's used both in and out of the office.
- Caregiver/s or parents rather than mother and father
Other ideas that would affect your psychological professional's treatment of other people:
- Sex doesn't necessarily mean "male-female intercourse" in which a male penetrates a female, especially in GLB relationships. Asking different people to define "sex" can yield some really interesting conversations.
- For some odd reason people get really wrapped up in the idea of someone with a GLB orientation having sex. You don't think about your heterosexual friends' bedroom practices every time you see them, nor do you focus exclusively on sex when you talk about their relationships. Just as emotional attraction is important in heterosexual relationships, it's important in GLB relationships.
One of the best ways to understand this if you strongly identify as straight is to imagine a world in which males are "supposed to" be with males and females are "supposed to" be with females. (They do match, after all.) Now imagine feeling the way you do about people of the opposite sex in that world. Imagine being a woman who loves men (or a man who loves women) in a world where that's considered "bad" or "perverted" or a "sin." Would you be able to change your sexual orientation and start to be attracted exclusively to people of the same sex?
If thinking about this makes you uncomfortable, you're experiencing another psychological phenomenon known as cognitive dissonance, discomfort that results from a conflict in two thoughts, values, or behaviors, or some combination of the above.
Further reading: If you want to read more about removing sexual biases in language, visit the APA's article on Avoiding Heterosexual Bias in Language. 