I don't understand the debate here, nature vs nurture for what exactly? Just in general? I believe that we can't make sweeping statements like that because there are degrees for everything. Is this about personality or a specific trait, ability, behavior or aspect? For more defined topics, such as the ever-constant debate over homosexuality, tendency towards violence, addiction, etc., it makes more sense to ask the question and then go from there. I would say it has to be understood that near everything is a combination of biological background and environmental influences. I feel that it's ignorant to not look at all the variables in any given situation, so "believing" in one side or another doesn't mean much to me. I see it as more of a question as "Which do you think has more/guiding influence on this aspect of personality/behavior?" An argument can be made for any degree in any case because we as humans are so amazingly different in experience and makeup from one to the next, and because it's certainly not an exact science. Of course, all IMHO.
Child/Developmental psychology is fascinating if you're interested in these kinds of questions, I highly suggest pursuing a class at your college or university if you can! Psych in general is so valuable to study because it is applicable to almost every situation. My own focus is in personality along with social psychology, I study towards a masters in both Organizational Behavior and Industrial Organization, basically the business/corporate applications, and after that a PsyD. If I had more time or the option to take even more classes, I'd definitely take some philosophy, child psych and dev psych classes purely out of interest, but it's just not realistic financially or time-wise. Oh well, there's always the chance later in life. Good topic!