as long as the two can consent, then yes, marriage should be equal. Animals can't consent.
Life in your opinion starts at conception, but the law and doctors disagree. But you're fine to believe that and that's what's great about this country. What's not fine is trying to impose your beliefs on others, especially if it tramples on their rights to believe that IT DOES NOT start at conceptions and can't get an abortion. That's where you cross the line.