According to researchers, psychologists and scientists, personal beliefs and physical appearance can also indicate intelligence.
Many scientific studies have been conducted to determine the cause of high IQs, and a lot of it boils down to genetics.
"And it found that the difference was not because of biological factors but the psychological interplay of parents and children." According to Reuters, "Researchers found that among 121 Canadian children between the ages of 3 and 7, those whose mothers had suffered morning sickness scored higher, on average, on certain tests of IQ, memory and language skills." Researchers at the University of North Carolina at Chapel Hill found that female and male adolescents with an IQ score below 70 or above 110 are more likely to be virgins.
The Penn State Collegiate reports the findings: "Adolescents with IQ scores ranging from 70 to 110 had the lowest probability of virginity, according to two researchers from the University of North Carolina at Chapel Hill. "Mariah Mantsun Cheng, a research associate, and J.
Lower IQ levels linked to mercury exposure in the womb costs the United States .7 billion a year in lost earnings potential." Daily Mail reports, "Young people who smoke regularly are likely to have markedly lower intelligence levels than those who do not smoke, and, according to the study of 20,000 young adults, the heavier the smoker, the lower the IQ.
Oldest sibling are usually smarter, but it's not because of genetics.
The New York Times writes, "The new findings, from a landmark study published [June 2007], showed that eldest children had a slight but significant edge in I. — an average of three points over the closest sibling.
"It also makes perfect sense that more intelligent people -- people with, sort of, more intellectual firepower -- are likely to be the ones to do that." CNN writes, "These preferences may stem from a desire to show superiority or elitism, which also has to do with IQ.
In fact, aligning oneself with "unconventional" philosophies such as liberalism or atheism may be ways to communicate to everyone that you're pretty smart." Again, this has to do with defying common ancestral tendencies.
"They also found that 63.3 percent of adolescent men and 81.6 percent of women with IQ scores below average have never had sex and most have had fewer experiences of romantic attraction." "According to the research, an adolescent with an IQ score of 100 was 1.5 to 5 times more likely to have had intercourse than an adolescent with an above average score of about 120 to 130." Numerous studies on identical twins (who have the same genes) versus fraternal twins (who share, on average, half their genes) prove that intelligence is inherited.