Because if that was the rule, I bet the support for women in combat units would crash.
We believe that if one has the Biblical conviction to stand one's ground, or to live and labor in a particular direction, we should never put our signature to anything contrary to that.
My daughters conscientiously believe that they should develop their homes as a ministry to the next generation, and to strengthen the core of the nation. That core is the Biblically-oriented, traditional family unit. For them to sign a Selective Service registration form just to avoid a conflict now, hoping that there will never actually be a draft, is duplicitous and can be used by a draft board to allege no conscientiousness.