What is the reason for Allah's description of the Houris as "Kawa'ib Atraab" (buxom companions of equal age)?

The description of the women of Paradise as "full-breasted, of equal age" (كواعب أتراب) refers to their beauty and youthfulness, and that they are equal in age and beauty, with no preference among them that would lead a husband to favor one over another. "Full-breasted" (كواعب) means young women whose breasts have not sagged due to their youth and strength. "Of equal age" (الأتراب) means they are of a similar age, which is the age of thirty-three. Their description as "of equal age" might be to indicate that their ages are equal so that none are preferred over others, or because they are of equal age to their husbands.