We all become less flexible as we age.
I will be more flexible than most.
How can I boast that?
It is a small benefit of parenting some very inflexible children. In middle-age my wife and I have been given a graduate level extended boot camp style program in enhanced flexibility.
Our natural bounds have been shattered.
Assuming a normal decay curve from our artificially elevated heights, we may expect a twenty year flexibility bonus.
It's good to have something to offset the accelerated aging associated with parenting special needs children.