What is gynecomastia what is its cause during neonatal period and during puberty

Gynecomastia is defined as an enlargement of the male breast or development of breast in males.

Cause of gynecomastia during puberty - Harmonal imbalance at the time of puberty causes gynecomastia.

It causes during neonatal period (Period of 28 days after birth) -When an estimated 60 to 90% of infants develop transient palpable breast tissue because of the passage of estrogens(Maternal Harmones).