[kayodelycaon]

I absolutely believe it could be 90%. And it happens a lot more often than people think. The estimated average across the general population is roughly 1 in 4 for girls and 1 in 6 for boys. The vast majority are by family (3 in 4).

But I'd hesitate to say that is conclusive without seeing how it is across other professions as well.

I suspect it's more strong correlation than strong causation without more data to the contrary.