Is Marriage a Requirement of Christians?

i believe having children in marriage is normative. To turn away from procreation in marriage for the sake of some worldly gain, rather than be motivated by god centred christ's exalting kingdom advancement, is a sin. But i don't regard all birth control, or better conception control, as sinful. Using abortiv patients that kill a conceived child would be sin but choosing not to conceive may not be a sin. Which means, it seems to me that the methods and the timing of such choices will become a matter of biblically and medically informed wisdom.