A wonderful site called "Grandma Got STEM" profiles grandmothers who have accomplished marvellous feats of technology, and aims to drive a stake through the heart of stupid, thoughtless phrases like "How would you explain that to your grandmother?" or "So simple my grandma could do it."
Shown above, Helen Quinn, "particle physicist, PhD from Stanford in 1967, and grandmother of three young girls."
I've never understood why geeks hold their grandmothers in such contempt.
Perhaps you are tired of hearing people say 'how would you explain that to your grandmother?' when they probably mean something like 'How would you explain the idea in a clear, compelling way so that people without a technical background can understand you?'
Here's a similar saying you may have heard: 'That's so easy, my grandmother could understand it.'
Grandma got STEM counters the implication that grannies (gender + maternity + age) might not easily pick up on technical/theoretical ideas by sharing pictures and remembrances from/of Grandmothers who have made contributions in STEM-related fields.