Recently I had X-rays of my spine taken. The doctor said I had really "tall" disc spaces for my age (55 years old). Is this a genetic trait?

Disc space height (DSH) may be genetic but it hasn't been proved or disproved. It does appear that patients in the tall disc group are younger males. They are more likely to have a higher body mass index (BMI). They are more often involved in work-related injuries compared to people with collapsed DSH.

Several studies have been done measuring disc spaces. Some researchers think this measurement can be used to predict the results of spinal fusion surgery.