SPP1 and fetal growth restriction: Research indicates that IUGR piglets exhibit significant differences in testicular DMRT1 and SPP1 gene expression, which may indirectly lead to reduced sperm production and impaired reproductive performance in adulthood by affecting the Sertoli cell function and extracellular matrix dynamics, suggesting that abnormal testicular development in IUGR pigs may originate from altered gene expression [15].