My Ph.D. is in Neurobiology. But when I applied to grad school, I applied to both neuro and psych programs, not really giving much thought to what my diploma would read a few years down the line. As it turned out, I was accepted to several neuro programs and zero psych programs, so my fate was sealed early on. But would it have made a difference in my career trajectory?
My general feeling is that there's quite a bit of overlap among the life sciences. In grad school, it was not at all uncommon for a single lab to have grad students from multiple programs -neuro, pharmacology, molecular bio, etc. Friends from my grad program have gone on to faculty positions in various departments as well. But despite the seeming flexibility of a Ph.D. in biomedical science, I see a lot of hand-wringing these days in applicants over whether they should get a degree in X vs. Y. Obviously, coursework will vary from program to program. But after that, how you define yourself as a scientist is up to you and the research you do through your graduate and postdoctoral work. To me, that factors far more into whether a search committee considers you a good fit than the official field listed on your degree.