You could potentially make DNA a 'protected class' of data, implying insuarance companies cannot look at it in their decision making, same as something like race.
The law however is only as good as it is being enforced. And if recent events is anything to go by, not having this data is generally the strongest protection.
The problem is a law can be repealed any time. Might take some heavy lobbying to get there but nothing is impossible.