I am assuming you have checked out their website:
http://www.unige.ch/dase/immatricula...atenglish.html. It gives a lot of info about things like entrance exams and language tests, which seem to be required no matter what program you will be in.
This site (
http://www.crus.ch/information-progr...rland.html?L=2) also gives some general information about the requirements for studying in Switzerland. The specific information about which international qualifications are accepted is only in German, French and Italian. Basically, though, a high school degree is not enough. For Geneva, if I understand the French, you need 2 years at a university or 5 AP exams including math and science:
"Diplôme d'études secondaires supérieures + 2 années d'études universitaires reconnues par l'université concernée
ou 5 Advanced Placement Tests. Les 5 sujets doivent inclure 2 langues, les mathématiques, un sujet en sciences humaines et sociales et un sujet de sciences (chimie, biologie ou physique). Note minimum pour les AP Tests: 3"
Good luck.