My grandmother, whom we called “Nana,” always loved children. Many times, she asked me to give her great-grandchildren.

In 2000, the moment finally arrived. But it didn’t seem to matter. Eagerly, tenderly I lay my newborn son in her arms. She sat motionless, her eyes void. No expression whatsoever. I searched her face, desperately hoping to see some sign of joy…of recollection…of unde...