Assessing some1's personality based on his or her blood type is popular in some countries. In Japan, for example, it is not unusual for some to ask, "What's ur blood type?" as a conversation starter. Advocates of this idea claim that people with type A blood are calm, responsible and suspicious; those with type B blood are open-hearted, moody, easily deceived; and so forth. It is also asserted that a person of one blood type may find it difficult or easy to get along with someone of another blood type. Based on this concept, some consider blood type to be an important factor when grouping students in schools, selecting executives at companies, or even choosing mates. Is there any proof that our blood type really determines our personality? Are there any religious teachings that touch on this matter