Fast Facts (Fetal Development)
- A human person’s life begins at fertilization when the father’s sperm penetrates the mother’s egg.
- From the time of fertilization, a baby’s unique DNA and genetic makeup are complete from sex to hair color to height as an adult.
- A baby’s heart begins to beat just three weeks after fertilization.
- Brain waves can be detected at six weeks after fertilization.
- At two months after fertilization, all of the baby’s organ systems are complete. The baby just needs to grow for the remainder of time in the womb.