Hi Marion,
If you can solve the riddle of P then you will do us all a big favour.
I can trace my family history back to 1676, with absolute certainty.
And there are only three of us that have, or have had P, and that has all been in the past 30 years. Me, my niece, and my sixth cousin (common relative born in 1723). So I am not a great advocate of the hereditary theory! Nor, smoking, drinking or diet.
Sorry for the waffle.
Regards,
Daryl