The term “nature versus nurture” is used to refer to a long-running scientific debate. The source of debate is the question of which has a greater influence on development: someone's innate characteristics provided by genetics, or someone's environment. In fact, the debate has been largely termed obsolete by many researchers, because both innate characteristics and environment play a huge role in development, and they often intersect.
Does the child of actors become an actor because of genetics, or because he or she is raised in a household where acting is encouraged? Late 20th century studies on the nature versus nature debate seemed to suggest that it's a bit of both. Historically, though, some people believed that innate nature played a critical role in development. People were born to be poor, athletic, or any number of other things, and nothing could change this eventual fate.
Other people believed that the way in which someone was raised was the critical factor, and that people raised to be politicians, for example, would become politicians. People who believed that nurture was the primary influence were sometimes referred to as proponents of the “tabula rasa” or “blank slate,” referencing the idea that they thought everyone had the same potential at birth.
This black and white view of human development was termed the “nature versus nurture debate” to differentiate between the two sides of the argument. Well into the 20th century, researchers performed studies looking into the issue, and argued heatedly on both sides. Twin and sibling studies proved especially valuable, because researchers could use people with similar genetic material (nature) to see how their environment (nurture) influenced them.
Some things are obviously nature. Blue eyes, for example, are genetic, and eye color cannot be influenced by environment, although people could use colored contacts to change their eye color. On the other hand, language is a matter of nurture, determined by where someone is born. Something like height, however, is a cross between the two. Someone could be born with a tall gene, but be malnourished in childhood, resulting in stunted growth and a failure to develop as expected.
Most biologists today agree that the nature versus nurture debate is too simplistic. Heredity and environment both play a critical role in development, making both important considerations. One might as well ask about what's more important to the area of a rectangle, the width or the length, as psychologist Donald Hebb once did when questioned about the nature versus nurture debate.