VinnieFMaybe it's different in the States, but here getting a specialization makes you more competitive in that field than a double major does in either of the two fields, so generally it's better looked upon for graduate studies since you'll ultimately only end up focusing in on one specific area.
In the states you can go into Medschool with any type of degree, but the main determining factors are GPA, MCAT (Medical School Admission Exam) Scores, and School you graduated from.
To do well on the MCAT you must study, a lot. So with a background of Biology, Chemistry, and other Medical-like classes in college will help you with the MCAT. That is why I'm taking them.