OMG, this is the most immature thread I've seen on this forum, but I have to clarify some stuff -- it's not as simple as "sexist men prefer big boobs."
I took an anthropology class and we talked about this. Generally speaking, straight men prefer a WHR (waist-hip-ratio) of .7 because it's supposed to show optimal fertility and genetically quality. It's basically the human version of the peacock tail. The unbound SHBG (sex hormone binding globulin) is what accesses the cells in breast tissue and would allow increased size. SHBG levels are largely genetically determined. The whole idea is, if you are able to invest in such a costly and inefficient storage of fat/development of tissues, you would have superior genetic quality just like a peacock would if he was able to invest in a huge colorful tail.
You could then say a man that is "sexist" (this is a broad and vague description) might be more concerned about such frivolous traits or cultural factors have influenced them to see physical traits as more important and thus, objectify women, but the statement "sexist men prefer big boobs" just sounds like tabloid rubbish.
BTW, the whole physical display of genetic quality thing has also applied to other things like voice pitch, facial symmetry, and even scents people give off in sweat.
~hugs~
