The Biology of Belly Buttons
A belly button is a universal characteristic for most placental mammals, including humans. It serves as a reminder of their early development.
During gestation, a fetus relies on its mother for nourishment and waste removal. This exchange occurs through the placenta, which attaches to the mother’s uterus.
The umbilical cord, a flexible tube with blood vessels, connects the fetus to the placenta. These vessels transport oxygen and nutrients from the mother’s bloodstream to the fetus. Waste products are carried back to the placenta for disposal.
At birth, the umbilical cord is no longer needed. It is clamped and cut a few inches from the baby’s abdomen. The remaining stump dries and falls off within weeks, leaving the navel, or belly button.
Cloning and Fetal Development
The question of whether a clone possesses a belly button often arises from misconceptions about how cloning works, particularly as depicted in science fiction. Reproductive cloning, most commonly achieved through a technique called Somatic Cell Nuclear Transfer (SCNT), involves taking the nucleus from a somatic (body) cell of the animal to be cloned and inserting it into an enucleated egg cell (an egg cell with its own nucleus removed). This reconstructed egg, now containing the genetic material of the donor, is then stimulated to begin dividing.
The developing embryo, genetically identical to the donor animal, cannot grow outside of a maternal environment. Therefore, this early-stage cloned embryo is implanted into the uterus of a surrogate mother. Once implanted, the cloned embryo undergoes the same physiological developmental processes as a naturally conceived embryo.
This includes the formation of a placenta, which establishes the connection to the surrogate mother’s bloodstream for nutrient uptake and waste elimination. An umbilical cord then develops, linking the cloned fetus to this placenta, just as it would in any natural pregnancy. The cloned fetus receives all its sustenance and eliminates waste through this umbilical cord and placenta throughout its gestation.
Upon reaching full term, the cloned animal is born through a normal birth process. Similar to naturally conceived offspring, the umbilical cord is severed after birth, and the remaining stump eventually heals to form a belly button. Therefore, because reproductive cloning involves uterine development within a surrogate mother, complete with a placenta and umbilical cord, cloned animals do indeed have belly buttons, just like their naturally born counterparts.