One huge advantage of knowing about family history is that sometimes it can help you to trace and pinpoint occurrences of illness.
My father and two of my brothers had all died of heart attacks at a fairly young age. My dad and my eldest brother were in their forties, and my younger brother was just thirty two years old.
In tracing back my paternal side of the family, I discovered that rarely did any of the males live beyond the age of forty four, and many had died of heart disease before they reached the ripe old age of forty. The females in the family line hardly ever suffered with any heart trouble at all.
It occurred to me that the heart disease in the male line was too frequent to be coincidental, especially as it all seemed to be because of high cholesterol levels, leading to a fatal heart attack.
Once I had concluded my investigation, I discussed this with a heart disease specialist, and after examining all my paper work, he called my nephews in for medical checks. In two of my three nephews, he discovered that they had severe cholesterol levels (above the 15 mark) and needed immediate medication.
The information was too late to save my dad and brothers, but at least my nephews are okay.
A different branch of family history, but a useful one.