The Childhood of Interests is a ribald poetic form intended to express grief over immortality, originating in The Diagnostic Grandparent. The rules of the form are applied by poets to produce individual poems which can be recited. The poem is three to four couplets. Use of internal rhyme is characteristic of the form. Forms of parallelism are common throughout the poem, in that certain lines often share an underlying meaning and they are required to maintain phrasing. The ending of each line of the poem shares the same rhyme. The second line of each couplet reverses the word order of the first line. The second line of each couplet must expand the idea of the first line.