Getting dental assistant positions can be tricky and difficult because there are a number of reasons they may choose not to pick you:
1) If they know you're applying to dental school and want someone long-term... but offices vary from dentist to dentist. Some are willing to train and it depends on the circumstances. If you still have a year to go before matriculation, then some offices will be okay with that, but other offices won't. (I learned that the hard way)
2) If they want a certain number of months/years of experience (which means someone who is experienced that applies for the job will probably end up getting the job over you)
3) You need an X-ray license, probably the most important criteria to them
For several months, I went on 5-7 DA interviews and didn't get the job. Eventually, I was able to find an office that accepted me but that comes with a little bit of luck I think.
It probably doesn't matter if you are male or female for the job, I don't think.