You DID do something ethically and morally wrong. You made an outrageous claim about the biology of conception that has absolutely no scientific support. I view that as unethical. In so doing, you implied that any woman who did get pregnant as a result of rape must not have legitimately been raped. Like maybe they didn't fight hard enough. Or maybe they enjoyed it just a little. I view that as immoral.
I'm not saying you should get out of the race. Heck, I want McCaskill to win, and right now it might well be that you staying in is the best thing for her. I'm just saying it would be nice if you could view this as a teaching moment. Recognizing that you are the one who needs to be taught something. About your views on women and sex. About your unfortunate apparent willingness to ignore science in favor of your pre-set political and religious views. But why bother with any of that when you'd just rather yell at that darn liberal media. Yep, you've definitely chosen the more productive path.