You inherited your blood type from your parents (and, in turn, from ALL your ancestors) so this article appears to be genealogy-related:

The idea has deep roots in Japan’s cultural past, but a watered-down version is increasingly popular in Asia and even America.

In Japan, there is a belief that a person’s personality is linked to their blood type. This may sound strange, but the idea is not too dissimilar to astrology’s popularity in the UK or the US today. However, Ketsueki-gata, as it is called, is unique and has deep cultural roots in Japan’s recent history. While it may seem trivial to us, in Japan a person’s blood type

 has important implications for how they are understood as an individual and how they may perform in their jobs. So what’s going on here?

What does your blood type say about you?

Okay, let’s get the fun part out of the way first. For the curious out there, this is what Ketsueki-gata says about the different blood types.

Type A blood: According to a casual internet search, people with Type A blood are regarded as warm, friendly, and compassionate. However, they can be obsessive, stubborn, and uptight. Type A individuals are said to be more common in Japan that people with other blood types.

Type B blood: Individuals with Type B blood are thought to be strong, passionate, decisive, and empathetic, but they are also more selfish, erratic, unforgiving, and wild. People with this type of blood are seen as being quite transitory, taking up projects and then leaving them half-complete.

Type AB blood: If you have AB type blood, you get the best of both worlds. According to Ketsueki-gata, you’re likely to be regarded as rational, composed, sociable, and adaptable. But you can also be unreliable, critical, indecisive, and aloof. AB type blood is the rarest in Japan, so people with it are often seen as eccentric.

Type O blood: These individuals are confident, strong-willed, optimistic, and natural leaders. But they are also competitive, insecure, and likely workaholics. According to this system of thinking, Type O people are not meant to get on with type A people.

There are other blood types out there – Ketsueki-gata was only designed to account for these main types.

You can read more in an article by Dr. Russell Moul published in the iflscience web site at: http://tinyurl.com/2yjya2ym.