Don't waste your time with those numbnut elders. The only thing they know is what they're told to know. They don't think. They don't reason. They react...and they react as the WTS has taught them to. They will not be able to fill in the blanks on how doctrine has changed. In their mind, it has never changed. Any challenge to them will be ignored. They're not there to listen to you...they're there to either straigten you out, convert you or convince you to allow them to train your children in their cult religion.
If you are not a JW, if you're an unbelieving mate, just tell them it's none of their business regarding what you will or will not allow our children to do. As an unbeliever, you don't accept their theology, nor their authority over your household.
If you're a fader, well, you're going to have to tread more lightly, if you're trying to stay faded. Though if they're wanting your permission for the kids to attend, I'm guessing that you're not a baptized JW.
Even if you choose to spar with them over WT doctrine, do yourself a long term favor and do not give anyone explicit permission to push the WT religion on your children. Even if you allow them to attend certain meetings here and there, make sure they attend other services elsewhere, for comparison's sake. Give them room to grow and experiment on their own path of spirituality.