Hi indiarose,
it's true that people with a family history of arthritis are a bit more likely to develop arthritis themselves. This may be because of heritable abnormalities of the joints that make them more vulnerable. However, this does not mean you will definately develop joint problems, it just means you are at an increased risk.
I have arthritis but neither my mother nor father have ever had any problems with their joints. And the myth about toes overlapping is rediculous! This may just happen to some people for reasons not related to their arthritis.

Hope my comments help,
boudica