Knowing you have a high susceptibility to a significant disease could have all sorts of implications for insurance - medical, life and even car.
In general insurance companies require you to disclose any and all information that you have that would be pertinent to them assessing risk. Clearly for medical and life insurance you knowing there is a high chance you will get Parkinsons (for example) is information your insurer would like to know - and presumably will have a negative impact on your coverage costs/availability.
Here in the US there are currently laws - such as Genetic Information Nondiscrimination Act (GINA) - to prevent insurance companies demanding this information.
However laws can be repealed. The insurance industry is the 'leader' in government lobbying. 23andMe is still subject to US federal subpoenas laws. 23andMe could be aquired by an insurance firm.
Also consider laws differ in other countries, where insurance companies might be able to legally demand results. In Canada insurance companies can not only request it, they can demand you get this kind of testing before you can obtain coverage.
Consider further that databases can be hacked/stolen (it seems to be happening to every email marketing company right now).
Think carefully whether you want your personal legal name and contact details all over the results of a test like this.