Fetal surgery has come of age. For decades experimental fetal surgery proved essential in studying normal fetal physiology and development, and pathophysiology of congenital defects. Clinical fetal surgery started in the 1960s with intrauterine transfusions. In the 1970s, the advent of ultrasonography revolutionized fetal diagnosis and created a therapeutic vacuum. Fetal treatment, medical and surgical, is slowly trying to fill the gap. Most defects detected are best treated after birth, some requiring a modification in the time, mode and place of delivery for optimal obstetrical and neonatal care. Surgical intervention in utero should be considered for malformations that cause progressive damage to the fetus, leading to death or severe morbidity; that can be corrected or palliated in utero with a reasonable expectation of normal postnatal development; that cannot wait to be corrected after birth, even considering pre-term delivery; that are not accompanied by chromosomal or other major anomalies. At present, congenital hydronephrosis is the most common indication for fetal surgery, followed by obstructive hydrocephalus. Congenital diaphragmatic hernia also fulfills the criteria, but its correction poses more problems, and no clinical attempts have been reported so far. In the future many other malformations or diseases may become best treated in utero. The ethical and moral issues are complex and need to be discussed as clinical and experimental progress is made.