Gender, Sex, and Sexuality for Multi-Species Stories
So you're writing about a species where gender, sex, or sexual orientation are a little more... complicated than for humans?
Here's my terminology guide for sci-fi, fantasy, and non-human gender and sexual orientation.
Biological Sexes:
Female: The gender that lays eggs or produces the egg cell to be fertilized.
Male: The gender that fertilizes eggs.
Hermaphrodite: An organism with the sexual organs of both genders. Usually refers to entire species, and refers to the typical state of affairs within these species. Hermaphroditic organisms may or may not be able to reproduce on their own, but when engaging in sexual reproduction they are able to either impregnate or be impregnated. Use this word for non-human species that fit this description. Many plants and some animals are hermaphrodites. Gender and sexual orientation may or may not be meaningless to hermaphroditic species; some adopt gender labels out of convenience or preference. Sequential hermaphrodites, which switch from one biological sex to the other during their lifetimes, may or may not switch from one gender identity to the other as well.
Intersex: An atypical condition found in species with two or more genders; refers to those individuals which cannot easily be categorized, physically, as one gender or the other. May be attracted to either gender, both, all, or none; may have any gender identity. Ex: Intersexed person, gender identity male, attracted to females, would be heterosexual; if gender identity is female, then homosexual. For human intersexed people, the term "hermaphrodite" is near-always incorrect and usually considered offensive because Earth-humans are familiar with hermaphrodites only in terms of relatively simple animals; calling an intersex human a "hermaphrodite" is equivalent to calling them, for example, a slug. Exceptions may exist for genetically engineered humans which fit the biological definition of hermaphrodites in sci-fi continua.
Asexual (Biology): The condition of having no gender. Refers to entire species; for example, amoebas. May reproduce by fission, spores, etc. Gender identity and sexual orientation are probably meaningless to these species; some adopt gender labels out of convenience or preference. Since they do not reproduce sexually, these creatures may not have a sexual orientation, or may be asexual in terms of sexual orientation.
Third, fourth, etc. genders: Your species may have multiple genders, each with a different role. You will have to name these yourself. Some species have an infertile third gender to care for young (ex., worker bees).
Gender Identities:
Female/Male: Social, personality-based, brain-based gender. Distinct from biological sex but usually consistent with it.
Agender; nongender; gender-neutral; androgynous: Some of the many words used to describe people who identify as having no gender. Applies to most creatures who are biologically asexual and many who are hermaphroditic, as well as some individuals from species with sexes. May be attracted to one or more genders, all, or none.
Genderqueer: As a general term, non-binary people in a species with a binary (or trinary, etc.) gender divide. May be attracted to one or more genders, all, or none. As a specific term, unlike agender (etc.) individuals, genderqueer individuals may identify as one gender or another at different times during their lifetime, switching genders. Sequential hermaphrodites may or may not be described as genderqueer.
Transgender: Someone with a biological sex that does not match their gender identity. Both the biological sex and the gender identity can be anything, including neutrois (physically non-gendered), as well as the binary (trinary, etc.) genders. Use their gender identity to describe their sexual orientation; for example, someone with a female gender identity, attracted to females, is homosexual even if their biological sex is male. Depending on the species, this may be a very typical condition or a very unusual one.
Sexual Orientations:
Homosexual/Heterosexual: Attracted to one's own/the opposite gender. This designation can only apply to people who have a gender identity, and usually in the context of a species with two main gender categories.
Asexual (Orientation): A sexual orientation found among species which reproduce sexually; lack of sexual attraction to all genders. Asexual individuals can identify as any gender or none at all. They may desire platonic romance and have gender preferences for partners, or not desire platonic romance at all. Most biologically asexual creatures can be described as asexual in orientation as well, though their species probably does not have a distinct concept of "asexual" unless they have been in contact with species which are not biologically asexual.
Bisexual: An individual, usually from a species which has genders, attracted to two of those genders. In species with three or more genders, "trisexual", etc., may be an appropriate category (but must be differentiated from the old "I'm trisexual; I'll try anything once" joke).
Pansexual: An individual attracted to other individuals regardless of gender. Different from bisexual in that it encompasses those who do not fit into the two genders that bisexual people are attracted to. Will still have preferences regarding age, personality, species, etc.
Androsexual; Androphilic: Attracted to males. Different from "Straight female" or "Gay male" in that it can be used to describe those who are neither female nor male, or are both.
Gynosexual; Gynophilic: Attracted to females; useful for describing those who are neither/both female and/nor male.
Xenosexual: Someone attracted to those from a different species from their own. Generally unusual, but some species are xenosexual by default (cf. Mass Effect Asari). Usually also has preferences regarding gender, age, etc., and may be attracted to one species, some, or all. Assumes sapient (able to consent) species only.
Omnisexual: Jack Harkness.
Sex Drives, Reproduction, and Families
Aromantic: An individual that does not experience romance in connection with their sex drive. For some species, this is the default situation; sex occurs without romance, as an instinct, a ritual, or a biological need, and there is little or no attachment between sexual partners. A good example in the animal kingdom: Cats. Cats go into heat, call for toms, and mate; then the toms have nothing more to do with them unless they were friends beforehand. Cats form friendly attachments, but not romantic ones. Species that are aromantic or tend to be aromantic may have a strong estrus cycle that forces them to reproduce as a biological imperative (ex., Vulcans). Some aromantic species may reproduce by spores, eggs, etc., and may never meet the other parent. Most aromantic individuals are capable of love; it just doesn't have anything to do with sex.
Monogamous: Attached to one other individual. Monogamy may be social (an exclusive pair-bond), sexual (exclusive sexual relationship), or both (a social and sexual pair-bond). It may be temporary (one breeding season), semi-permanent (as with humans; can be terminated by death, divorce, or "falling out of love") or permanent (Tolkien's elves, for example; bond for life upon their first sexual contact and will not re-marry if one dies).
Polyamorous: Just what it sounds like--loving more than one other person at once. Some species may have this as the norm; for example, bonobos (the classic example). Polyamory may involve the formation of "group marriage" style bonded groups (three or more people in an exclusive sexual or social group), or it may involve romantic pair-bonds with multiple people who are not also bonded with each other. Distinct from aromantic sexuality in that the bonds are emotional and often familial.
Hope that helps...
Here's my terminology guide for sci-fi, fantasy, and non-human gender and sexual orientation.
Biological Sexes:
Female: The gender that lays eggs or produces the egg cell to be fertilized.
Male: The gender that fertilizes eggs.
Hermaphrodite: An organism with the sexual organs of both genders. Usually refers to entire species, and refers to the typical state of affairs within these species. Hermaphroditic organisms may or may not be able to reproduce on their own, but when engaging in sexual reproduction they are able to either impregnate or be impregnated. Use this word for non-human species that fit this description. Many plants and some animals are hermaphrodites. Gender and sexual orientation may or may not be meaningless to hermaphroditic species; some adopt gender labels out of convenience or preference. Sequential hermaphrodites, which switch from one biological sex to the other during their lifetimes, may or may not switch from one gender identity to the other as well.
Intersex: An atypical condition found in species with two or more genders; refers to those individuals which cannot easily be categorized, physically, as one gender or the other. May be attracted to either gender, both, all, or none; may have any gender identity. Ex: Intersexed person, gender identity male, attracted to females, would be heterosexual; if gender identity is female, then homosexual. For human intersexed people, the term "hermaphrodite" is near-always incorrect and usually considered offensive because Earth-humans are familiar with hermaphrodites only in terms of relatively simple animals; calling an intersex human a "hermaphrodite" is equivalent to calling them, for example, a slug. Exceptions may exist for genetically engineered humans which fit the biological definition of hermaphrodites in sci-fi continua.
Asexual (Biology): The condition of having no gender. Refers to entire species; for example, amoebas. May reproduce by fission, spores, etc. Gender identity and sexual orientation are probably meaningless to these species; some adopt gender labels out of convenience or preference. Since they do not reproduce sexually, these creatures may not have a sexual orientation, or may be asexual in terms of sexual orientation.
Third, fourth, etc. genders: Your species may have multiple genders, each with a different role. You will have to name these yourself. Some species have an infertile third gender to care for young (ex., worker bees).
Gender Identities:
Female/Male: Social, personality-based, brain-based gender. Distinct from biological sex but usually consistent with it.
Agender; nongender; gender-neutral; androgynous: Some of the many words used to describe people who identify as having no gender. Applies to most creatures who are biologically asexual and many who are hermaphroditic, as well as some individuals from species with sexes. May be attracted to one or more genders, all, or none.
Genderqueer: As a general term, non-binary people in a species with a binary (or trinary, etc.) gender divide. May be attracted to one or more genders, all, or none. As a specific term, unlike agender (etc.) individuals, genderqueer individuals may identify as one gender or another at different times during their lifetime, switching genders. Sequential hermaphrodites may or may not be described as genderqueer.
Transgender: Someone with a biological sex that does not match their gender identity. Both the biological sex and the gender identity can be anything, including neutrois (physically non-gendered), as well as the binary (trinary, etc.) genders. Use their gender identity to describe their sexual orientation; for example, someone with a female gender identity, attracted to females, is homosexual even if their biological sex is male. Depending on the species, this may be a very typical condition or a very unusual one.
Sexual Orientations:
Homosexual/Heterosexual: Attracted to one's own/the opposite gender. This designation can only apply to people who have a gender identity, and usually in the context of a species with two main gender categories.
Asexual (Orientation): A sexual orientation found among species which reproduce sexually; lack of sexual attraction to all genders. Asexual individuals can identify as any gender or none at all. They may desire platonic romance and have gender preferences for partners, or not desire platonic romance at all. Most biologically asexual creatures can be described as asexual in orientation as well, though their species probably does not have a distinct concept of "asexual" unless they have been in contact with species which are not biologically asexual.
Bisexual: An individual, usually from a species which has genders, attracted to two of those genders. In species with three or more genders, "trisexual", etc., may be an appropriate category (but must be differentiated from the old "I'm trisexual; I'll try anything once" joke).
Pansexual: An individual attracted to other individuals regardless of gender. Different from bisexual in that it encompasses those who do not fit into the two genders that bisexual people are attracted to. Will still have preferences regarding age, personality, species, etc.
Androsexual; Androphilic: Attracted to males. Different from "Straight female" or "Gay male" in that it can be used to describe those who are neither female nor male, or are both.
Gynosexual; Gynophilic: Attracted to females; useful for describing those who are neither/both female and/nor male.
Xenosexual: Someone attracted to those from a different species from their own. Generally unusual, but some species are xenosexual by default (cf. Mass Effect Asari). Usually also has preferences regarding gender, age, etc., and may be attracted to one species, some, or all. Assumes sapient (able to consent) species only.
Omnisexual: Jack Harkness.
Sex Drives, Reproduction, and Families
Aromantic: An individual that does not experience romance in connection with their sex drive. For some species, this is the default situation; sex occurs without romance, as an instinct, a ritual, or a biological need, and there is little or no attachment between sexual partners. A good example in the animal kingdom: Cats. Cats go into heat, call for toms, and mate; then the toms have nothing more to do with them unless they were friends beforehand. Cats form friendly attachments, but not romantic ones. Species that are aromantic or tend to be aromantic may have a strong estrus cycle that forces them to reproduce as a biological imperative (ex., Vulcans). Some aromantic species may reproduce by spores, eggs, etc., and may never meet the other parent. Most aromantic individuals are capable of love; it just doesn't have anything to do with sex.
Monogamous: Attached to one other individual. Monogamy may be social (an exclusive pair-bond), sexual (exclusive sexual relationship), or both (a social and sexual pair-bond). It may be temporary (one breeding season), semi-permanent (as with humans; can be terminated by death, divorce, or "falling out of love") or permanent (Tolkien's elves, for example; bond for life upon their first sexual contact and will not re-marry if one dies).
Polyamorous: Just what it sounds like--loving more than one other person at once. Some species may have this as the norm; for example, bonobos (the classic example). Polyamory may involve the formation of "group marriage" style bonded groups (three or more people in an exclusive sexual or social group), or it may involve romantic pair-bonds with multiple people who are not also bonded with each other. Distinct from aromantic sexuality in that the bonds are emotional and often familial.
Hope that helps...