You wrote:
"I disagree. And Christian teaching is not "ancient". It, like God himself, simply "is"."
Okay, then you MUST believe that birth control is wrong if you're a professing Christian because it was always opposed by Christians until recently. Read Charles Provan's book called The Bible and Birth Control to see just how Protestants viewed birth control since they appeared in the sixteenth century.
I think Jesus and his disciples were pretty silent on the subject. Beyond that, we are pretty free. The Church of Christ thinks it is wrong to have musical instruments in church even though the Bible is VERY silent on the subject. It means that I play an instrument in church AND drive a Chrysler (about which the Bible is also silent), although I stole neither.