Sure, often this question about star signs is an icebreaker at a party, however it is not polite to ask about a person's blood type.

There's a strong skeptical element in our culture (I'd even say cynical), so asking someone's star sign is usually done in light-hearted social situations only. As for the blood type, we don't have that belief in Western culture. However, there is apparently a diet which matches appropriate food to blood type. I've had plenty of Korean friends ask me the question, and honestly I've never known my blood type. I asked my doctor, and the current medical opinion is that knowing your blood type is unnecessary: if you ever need a blood transfusion you will be re-tested on-the-spot, regardless of what you claim or if it's written on any of your medical/donor cards.

I think it is not impolite because you still have to decide, yes or no, in western countries they do that .. i dont know in china ???

Actually asking this question is very common in Western countries, but usually implies that you are interested in being romantic with the person you're asking the question to. It is thought of sometimes as "breaking the ice" which means to try to start up a conversation with someone you want to date. Asking someone's blood type at a first meeting is probably a worse idea, people in western culture would see that as creepy and probably think you are trying to collect blood. Hahaha!

Hi... I think there is nothing wrong to ask that but perhaps not at the first meeting...