What's the best way to deal with family members who disapprove of the parenting decisions you make?

Show them your point of view, and why you've made those decisions. Its best to tell them in a calm manner, so their less likely to start an argument with you. If you struggle with speaking them, you could write it down in a letter and give/send it to them.

By telling them you are doing the best to your ability. I know it will hurt but constrive critistim is a way of life.

Tell them that you appreciate their parenting critiques but that you know what is best for your children.

The best and the simplest way to deal is to talk. Just have a glass of wine or juice or something and sit together to talk about your decision. It is possible that they have a better sight of the world. On the other hand, it is also possible that your decision is right and they are unable to see it that way.

First of all, acknowledge that even the harshest judgement and criticism can be based on a caring desire to help, especially when it comes from family or friends. That can be really hard when we feel attacked or criticized. Sometimes a simple, "Thank you," and a smile is enough to shut down unwanted advice (even if you have no intention of following it. If you want to go a bit further and challenge it, something that acknowledges their desire to help can make someone feel listened to and respected: "I appreciate that you're trying to help when you say... but it makes me feel (judged / belittled / hurt / uncomfortable)... even if that's not what you intended." I find that most people back off immediately if you are that straightforward with them, or they will at least try to explain themselves if they think they've offended or hurt you.

you respectfully acknowledge their opinions but firmly remind them that this is you problem and that you will deal with it how you see fit.

Remind them that while you value them and their opinion you aren't always going to do things the way they think they should be done. You have to do what works best for you and your child.

I would tell the family members that the last time I checked, I'm the parent of my child. My child is not in danger and is healthy and happy. I would then tell them if they have a problem then it is not my concern. Back off.

In these circumstances it is always important to be tactful but firm. Regardless of what other might think, parenting is a very personal thing and while advice is often useful, judgement is not. I think the best way to deal with your situation would be to set your family members aside and have a heart to heart conversation. In this conversation cover the reasoning behind your parenting style, make sure they understand that although advice is appreciated, decisions are ultimately up to you, and end up by letting them know that judgement is unnecessary and not appreciated. The one thing to remember during this is that in order to be effective but not offensive one must be direct but tactful.

Tell them that everybody is different and that they may have done good with their kids but these are your kids and you need to learn for yourself.