does siblings more likely to have sex if in a nude familyWith questions like this, I like to remind people that nudity and sex are two different things. It is possible to have sex while being fully clothed, and it is possible to be nude around others without having sex. This happens all of the time.
That being said, it may be that siblings in naturist families are more likely to have sex. I'm guessing this would be not due to the nudity, but because I expect that there is significant overlap between families more open and comfortable about their bodies and families where sexual exploration isn't discouraged. This isn't to say that all naturist families would be accepting of sibling consanguinamory, as not all families are naturists for the same reasons.
As far as I know, there is no statistical data showing that sibling sex is more likely in naturist families than the general population.
what is the percentage of brother sister incest in divorce families
Now there may be some statistical information about this, but I suspect it might be about assault rather than consanguinamory. When it comes to consanguinamory, I would guess that divorce in and of itself is a less relevant factor than things like how much and how closely siblings are supervised. There are two-parent families with teenagers in which both parents are working full-time and then some, leaving the teen siblings home with each other and nobody else. On the other hand, there are divorced parents who closely supervise their teenagers. So divorce in and of itself probably isn't much of an indicator.
If, on the other hand, we're talking about adult siblings who have been through divorces themselves, then I think there is some likelihood that siblings in those situations either initiate or resume a sexual relationship, if for no other reason than their sibling is a "safe" partner after a painful experience of divorce.
is incest between two middle aged adults illegal in the uk
Yes, unfortunately. See here for more, and follow the links.