Final answer:
Queen Victoria was the first in the British royal line to have hemophilia, which she passed on to other European royal families through her descendants.
Step-by-step explanation:
A pedigree of the British royal family shows that Queen Victoria was the first in the royal line to have hemophilia, a genetic condition that she passed on to some of her descendants. This disease became known as the 'royal disease' because it spread to the royal families of Europe through Victoria's children who married into other royal families. Hemophilia is a blood disorder that impairs the body's ability to make blood clots, a process needed to stop bleeding. This condition can lead to excessive bleeding and health issues following injuries that would normally be minor.
Victoria's son Leopold, Duke of Albany, inherited the disease, and through other family connections, it also appeared in the royal families of Spain, Russia, and other European countries. The presence of hemophilia in the lineage of European royalty showcases the extensive interconnection within royal families across national borders, which is often tracked through detailed pedigrees.