-hood is the suffix indicating a place or condition, i.e. childhood, neighborhood, etc. At times I have considered the title of the Arthur Clarke novel CHILDHOOD'S END and have wondered if CHILD'S HOOD END might have been the better choice? Please entertain me with your conjecture or proof.
As a word modifier, a suffix isn't detached when the plurality of a word changes. Traditionally hood is a suffix, not a separate word. Although recently "hood" has been used as a shortening of "neighborhood", that's not a condition, which is what -hood in childhood means. There are words that could be used, by I agree with Mr. Clarke.