Trans
Trans has many definitions, but a good one is 'anyone who doesn’t entirely identify with the gender they were assigned at birth'. This encompasses, but is not limited to; transsexuals, transvestites and transgender people, as well as trans people with a less binary gender identity such as genderqueers and androgynes. Some trans people will fully transition, and may take hormones or have surgery to give them a body that matches their gender identity, others won’t, but will still live as their gender identity regardless of what body they have.
Trans people can be straight, LGBT or asexual and can (and do!) have fantastic romantic and sexual relationships. Relationships between one or more trans people will be different, and possibly slightly more complicated to relationships between non-trans people, but trans people shouldn’t feel pressured to tell a potential partner when they first meet them that they are trans. If you’re in a sexual relationship with a trans person, try to keep an open mind and be aware that a trans person might have issues with their body (e.g. someone may want to wear a t-shirt during sex)
In terms of sexual health for trans people, the bottom line is that most (if not all) of this guide is relevant to trans people as well as non-trans people. Trans people are as much at risk to STIs as anyone else, so it’s just as important to stay safe when having sex. This may require thinking in advance (e.g. standard condoms may not fit well on a surgically created penis or hormonally-enlarged clitoris)