Is this gramatically correct?

Can I ask you when you last had *** / (sexual) intercourse?

"intercourse" is a more formal or technical word. However, in a formal setting it may better to say "sexual intercourse" in full (I assume that is what you are referring to). In everyday language most people would just say "***", I think.

Outside a medical context, this is not a common question .

Clive

Apart from the choice word, this sentence is not grammatically correct. It is an embedded question which dictates the second question to have the same word order as a sentence. Your question should read as;

Can I ask you when you have had your last intercourse?

As explained, it is not a common question to ask, an alternative in more informal context would be;
When was the

hrsaneiYour question should read as; Can I ask you when you have had your last intercourse?

This is unnatural.

I am not a native speaker of English, so I can't trust my ear, but grammatically speaking, that's how it should be written.
I

hrsaneiI am not a native speaker of English, so I can't trust my ear, but grammatically speaking, that's how it should be written. I

"Can I ask you when you have had ..." cannot really be used in this way to ask about a single event in the past. If we change the unnatural "your last intercourse" to something more feasible, say "vaccination", we see it should b

I agree with you. The correct tense to use to refer to a specific time in the past would be past simple. My issue was with the the concept of embedded question. As you pointed out, the question should read as

Can I ask when you had your last vaccination? rather than Can I ask when have you had your last vaccination?

Hamid