DCST2 (DC-STAMP domain containing 2) is an essential sperm cell-surface protein required for mammalian gamete fusion during fertilization 1. As a member of the DC-STAMP protein family, DCST2 functions as a key sperm factor enabling sperm-egg recognition and fusion of spermatozoon to oocyte plasma membrane 1. Loss of DCST2 expression results in male infertility; male zebrafish with dcst2 knockout mutations developed normally with unaffected muscle biology but displayed complete infertility 2. Beyond its reproductive role, common genetic variants in DCST2 influence skeletal growth and development, with rs905938 genome-wide significantly associated with birth length (β = 0.046, P = 2.46 × 10⁻⁸), infant length, and adult height across large population studies 3. DCST2 expression is sensitive to environmental stressors; exposure to polystyrene microplastics downregulates DCST2 transcription in human spermatozoa along with other fusion-essential genes (DCST1, IZUMO1, SPACA6, SOF1, TMEM95), potentially compromising sperm functionality and fertility 4. These findings establish DCST2 as critical for both reproductive success and developmental growth regulation.