I should probably highlight at the start that if your parents reasoning for not accepting your Identity is because of their Religion, then there's honestly rather little you can do. Often times knocking such beliefs founded on religion requires shaking one's religious faith, and that in itself is a multiple year endeavor, that is only even possible if they're open to questioning their religion and the possibility of their God being false. Plus if they're the more aggressive religious people, you should honestly be valuing your safety over your parents acceptance. That's not to say don't continue being you, just make sure not to put yourself under religious fire over it while you're still dependent on them. Because people have been thrown out of home over this stuff before.
However, assuming otherwise?
This is honestly something really dependent on the specifics of your situation, so I'm going to give some estimate/general scenarios and solutions below but none by any means an exact or precise science.
It's also important to remember that for 16 years your parents have probably raised you and looked after you as if you're a boy. There is sixteen years of hard wiring with your parents there, that's not something you're going to shake free of over night. So if this is just a case of they're not used to it yet, what you might be able to do is simply continue to live your life as you identify, don't make it a point of rebelling though, just carry on with life normally. Bring it up with your parents where relevant, but take no strong efforts to either hide it or force it on the table either. Overtime your parents might be able to adapt and get more comfortable with it, and eventually grow more curious about it. Which is when you can try to fill them in on the details of such a thing, and overtime have them be accepting.
If this is more of a scary/intimidation thing, where they've been fed more negative images of the LGBT community but aren't innately hostile you *might* want to get the facts out to them sooner. Explain how you're still you, that you just don't feel, identify like a male. Clarifying that you're still you can reassure your parents worries a lot, especially the image some sheltered parents have of LGBT is the "Dildo hat, rainbow marching band" sort of people. I quoted *might* though because depending on the individuals your parents are, such fear might require more space and time to process the news. Hopefully it's the former, but if it's the latter then giving them more breathing room is important simply so they don't panic or think something vile is being forced on them.
If they're heavily religious but not aggressive? As in say they really like the Bible, but aren't the kind to hold hostility to the LGBT community (though disapproval might still be there) then once again you should aim to explain to them that you're still you. That this doesn't change the person that you already are. And *depending* on them, you *might* also want to use the Bible. Now if you choose to do this I suggest heavy caution, because most likely they'll see it as their religion being twisted against them. However, if they're the kind who are actually willing to sit down, discuss the Bible and are open to different interpretations (they aren't too common, but they're out there)
it could act as a very good way to reassure them religiously that everything is fine.
(EDIT: That last paragraph though mind you is a very specific scenario, I'm merely mentioning it in a the small off chance that your parents are the "sit down and legitimately discuss the Bible" kinds. In the vast majority cases of religious parents, I would avoid getting the Bible involved like the plague).
And I would cover what to do if they're minor/casual Christians.
But in all honesty I'm doubting this is the case since you specifically mentioned they value their religion over yourself at times.
Which seems to suggest your parents religious beliefs are more extreme in nature.