Total RNA was extracted from fetal penile tissues using TRIzol Reagent (Invitrogen) according to the manufacturer's instructions. RNA concentration and purity were determined using a NanoDrop spectrophotometer, and RNA integrity was assessed using an Agilent 2100 Bioanalyzer. RNA sequencing libraries were prepared according to the manufacturer's instructions and sequenced on an Illumina NovaSeq 6000 platform using paired-end sequencing.