child born of older parents
Refers to a child whose parents are relatively old at the time of birth.
See also: 年寄りっ子
He is a child born of older parents; his parents are already in their 60s.
child raised by grandparents; child spoiled by doting grandparents
Often implies the child is pampered or overindulged by grandparents.
See also: 年寄りっ子
Spoiled by my grandmother, I grew up like a child raised by doting grandparents.
Compound of 年寄り (toshiyori, 'old person') and 子 (ko, 'child'). The exact historical derivation is uncertain, but the word straightforwardly describes a child associated with older people.