Can you help me to understand what I am doing wrong that -1 keeps getting appended to the alias of my blogs.

I keep trying to save a test blog of a scientific study summary and need to use the title of the study as the title of the blog. Unfortunately I keen removing the -1 but it keeps getting added back!

I know there is a reason and a cause and maybe if I understood why it keeps doing this I could prevent it.

I want:
effects-of-a-very-low-fat-high-fiber-diet-on-serum-hormones-and-menstrual-function

and not:
effects-of-a-very-low-fat-high-fiber-diet-on-serum-hormones-and-menstrual-function-1