I second the motion of El/Jay Cathy.

Male birth control pills (there already are - but they have some untoward effects so it needs some polishing up - and some are still in development) and condoms work the same in preventing the meeting of the female egg cell and the male sperm, hence no pregnancy, no problem.

Female birth control pills on the other hand work by making the uterus hostile to the fertilized ovum. The fertilized ovum, to developed further need to implant into the uterus to get nutrients and oxygen. If it is unable, there is cell lysis and no pregnancy. It is technically a very, very early abortion. And that is where law, ethics and religion get in the way.