Mixed feelings here (and it does not apply to us as we are no longer in the UK). On the one hand, I think we would all agree that info that can help beat some of the nasty diseases around, be in cancer, diabetes, heart problems, etc. would be an excellent idea. Having access to that info for all- would give a much better overall picture, show up clusters, geographical differences, etc. And if it can help, then I am all in favour.
On the other hand- I have great misgivings about giving info which will decide on insurances, etc. Although to be quite honest, insurances have had access to our records for a very long time. If you want a mortgage, life insurance, private health insurance, etc- you already have to give permission for them to write to your GP and get a sinopsis of your health (the bane of GPs btw- it takes hours and hours and has to be done in the evenings and week-ends on top of everything else). We had huge difficulty getting a mortgage, as OH had renal failure after contracting a strep throat which was not treated in time. GPs cannot lie when asked for résumé of records for the above purposes (and you have no choice about giving permission, or they will just turn you down).
I'd like to understand a lot more about why and how before making that difficult decision.