This is a tough subject and I know I am probably going to get blasted for some things that I may say, but here goes.
I think that if you are going to be responsible enough to be joined in a sexual RELATIONSHIP with someone, you need to take a certain amount of ownership over one another. Part of you no longer belongs to just yourself. (Please keep in mind that what I am writing below has to do with ESTABLISHED relationships.)
Both men and women should have to have counseling before donating sperm or eggs. I feel that if the are married or in a domestic partnership, the SO should have to attend the counseling appointment as well. By doing this, all parties at the very least have knowledge of what the other party intends to do and will be given insight as to why they are making this decision. By hearing each other out you may be learn to accept their donation or the opposite, they may hear out your reasons you are against it and decide to not go through with it. This is all about communication people!
Now, I have read some people think it is unfair for a woman to get to say what a man can do with his sperm, but she can decide what to do if a baby is conceived without his consent. I feel that this is a bit different because (depending on your view, but this is MY view) you are dealing with an actual existing life, not one half of what COULD become a life. Once again, before anything is decided, I think that counseling should be required. If the woman wants to keep the baby and the man wants nothing to do with it, it should be like a closed adoption situation. You do not tell the name of the father, all you get is a family medical history, and NO CHILD SUPPORT. He signs away ANY AND ALL RIGHTS to this child. Now if it is the opposite and the woman wants the abortion while the man does not want her to get the abortion, (this is where I will probably lose followers and get blasted) I think that she should not bee able to terminate the pregnancy. I understand that it is her body and such, but half of that being belongs to someone else who wants it. I have seem some of my friends go through this and the man had to get some counseling after she went behind his back and got the abortion. Then another friend who is now a GREAT single dad because she did listen to him with a mediator and kept the baby, but after her birth, she did as I suggested for the men above: signed away all rights, and has no contact whatsoever.