Hemophilia is a genetic disease that has plagued the royal houses of Europe since the time of Queen Victoria, who was a carrier. Her granddaughter, Alexandria, married Nicholas II, the last czar of imperial Russia. Alexandria was a carrier for hemophilia, but Nicholas was normal. Their son, Alexis, was afflicted with the disease. Alexis and his four sisters were all killed in 1917. Based on this scenario, it is most likely that:

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As hemophilia is a recessive X-linked genetic disorder, it can only be inherited from the mother who is a carrier. Since Queen Victoria was a carrier and passed the gene to her daughter Alexandria, who in turn passed it on to her son Alexis, it is likely that each of the four sisters had a 50% chance of being a carrier of the gene. It is possible that some or all of them may have been carriers, but since they did not have any affected children, it is more likely that they did not pass on the gene to their offspring. There is no evidence to suggest that any of the sisters had hemophilia themselves. Alexis could not have inherited the gene from Nicholas, as he was normal and did not carry the hemophilia gene.

Hemophilia Is a Genetic Disease That Has Plagued the Royal