Legally, a baby is considered alive when it is fully expelled from the uterus with a beating heart or voluntary breaths, pulsating umbilical cord and voluntary movement of their muscles, which is known as the "born alive" status. However, philosophically people may take a different view to the point a fetus is considered a live person.
Under U.S. law, the born alive status applies to any infant born vaginally, via cesarean section or from an induced abortion. However, many people debate when a fetus is classed as alive and their views differ according to their religious or cultural status. Some believe life begins at the point of conception, and there is no medical consensus on where life begins, as determining an exact point is difficult.
Biologically, some may consider a zygote as a living organism, as it grows, respirates, reacts to stimuli and has a metabolism. However, it cannot exist independently of the organism it depends upon for many months, even with assistance outside the uterus, which presents a challenge to this argument. Some may therefore define life as beginning when this occurs, which is around the 22nd week of gestation.
Other means of determining when life begins may include when the fetus begins to draw breath outside of the uterus, or at the point of implantation when the mother becomes aware of the pregnancy. Owing to the diverse range of views on this debate, establishing a non-legal stance that everyone agrees on is challenging.