If you are a cis person talking to someone who's dating a trans person, there are some things you should never ask. It's okay to want to understand things you don't have much knowledge or exposure to, but it's also important you avoid these questions. 

How do you have sex?

This is one of those questions that people don’t ask their friends in cisgender relationships. Throw a trans body into the relationship and suddenly people think it's acceptable to ask about private and intimate details. 

Are you gay/straight now?

This question comes up when a straight cis man starts dating a trans woman or a gay cis man starts dating a trans man. When you ask this question, you're assuming you know what genitalia this transgender person owns, and insinuating that genitalia equates to gender. That's not true.

Trans women are women, and trans men are men. In the example above, the man is still straight because he’s dating a woman. The gay man is still gay because he’s dating a man.  

What surgeries has he/she had?

People ask this question with good intentions and from a place of curiosity, but it really isn’t appropriate. This information is not relevant to anyone but the trans person and sometimes the partner in the romantic relationship.

There is no “one” surgery just as there is no end point to ones transition; men are male as soon as they identify as male, and women are female as soon as the identify as female. Some trans people decide to not transition medically, which means they do not take hormones or undergo surgery. Some trans people need surgeries to feel more comfortable in their bodies and identities and the extent of those surgeries varies depending on the person and their needs.

Does your family know?

This question is problematic because it puts unnecessary pressure on the couple. Some trans people live stealth and prefer that nobody knows their trans status so a partner of a trans person’s family may never know.

The trans person is not dating the family so there is really no reason for them to come out unless they want to, it’s somehow necessary, or feel like the right time.