、。
Parents might favor the youngest child.
Literal
Parents [topic-は], youngest-child [object-を] might-show-favoritism.
えこひいきする means 'to show favoritism' — from 依怙贔屓, technically a 四字熟語 but almost always written in hiragana. かもしれない (might/may) expresses possibility without certainty. 末っ子 (youngest child) uses the suffix っ子.