The cholesterol forms weak attractive forces with multiple phospholipids in the bilayer. would this increase or decrease flexibility of the membrane?

This would increase the flexibility of the membrane.

Explanation:

Studies with isolated plasma membranes reveal that their most abundant components are phospholipids, cholesterol and proteins. These biological membranes are fluid like liquid paraffin. Cholesterol is one of the responsible for this cell membrane fluidity. This is because cholesterol molecules prevent carbon chains from interacting potently - which would result in a gelatinous state of the membrane. Therefore, we can conclude that if cholesterol forms weak attractive forces with multiple phospholipids in the bilayer, this increases membrane flexibility.

it's unlikely a majority of a large population would agree on issues

hope this : )

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."