There is a point in which a person can not be held responsible for what someone else does with what is given to them.
I would illustrate this as a bit like paying taxes. I am legally obligated to pay taxes, and I am told by the bible to pay my taxes. But I don't agree with how the government spends some of tax dollars. I can say that I am anti war for one thing.Still I can not be held responsible for how the government decides to use my tax dollars. So I for one do not spend a lot of time thinking about my tax dollars, and what they may have been spent on.
A number of large charities are run much like the government. You don't have any control over how your gift is going to be used. I doubt that God will hold against you if it's spent on something you don't agree with. It doesn't mean though that the charity isn't still worthy of support.
I also believe that anytime you give to a charity, that you are giving a gift. Once a gift is given, you no longer have a say in how a gift is used. So continue to give with an open heart, and enjoy the thought that you have done the best you can.
As others have noted Planned Parenthood does so much more than just abortions. If 90 percent or more of the donations are used for the overall good of the community, and you believe in another persons right of choice, then I just don't understand the problem. Your support for PP, will never require you to have an abortion. It may be that any single one of your dollars will ever be spent on an abortion.
I personally could never consider having an abortion. But then I also believe in very strict morals, so I have never found myself in the same place as other women have. I will say though, that I did face the issue with one of my daughters. We learned before she was born, that she was not going to live very long, and would be facing major health problems. I made the choice to give birth to my daughter, but too this day I could never fault another woman for let a child like my daughter go before she was born. That is the right of personal choice. I am not on this earth to police anyone else, but myself.
I think you could drive yourself crazy trying to figure out a totally safe charity. Perhaps by simply giving to your church, you can have the security, that your charitable donations will be used according to your beliefs. I have done this myself, and I have faith that most, if not all my gift has been used to help others. It's nice to know that my church doesn't have any paid clergy, and low overhead costs.
Another option would be to give to the American Red Cross. As far as I can tell they are using the donations for disaster relief, and helping people in crisis. There is simply a time to let go of what you want, and let the gift of a charity donation, simply be a gift given with an open heart.
The people that then use the gift given, are the people that will need to answer to your higher power, and not yourself.
