How many Christians like that do you know?
How very perceptive of you to know whether a childless couple has no children because of their use of birth control or they're infertile. Just by seeing them, eh?
Or do you go up and ask them why they have no children?
Or do they just volunteer the information to you or did you hear it through the grapevine?
My sister has epilepsy. She takes anti-epileptic medications and has done so since the age of eight. She can NEVER have a child because she can NEVER stop taking these medications. These medications are known to cause severe birth defects. Because of this, since the age of eight years old, she has known that getting pregnant is an impossibility for her. If she stops taking these medications, she will most likely die.
When you say that people who use birth control do not have God’s grace, you are ignorant as to why some women MUST use birth control. And to top it off, you are judging someone’s soul based on this? I pity you.
"So then every one of us shall give account of himself to God. Let us not therefore judge one another any more: but judge this rather, that no man put a stumbling block or an occasion to fall in his brother's way." Romans 14:12-13 (KJV)
Translation: God decides. Not verdugo.