What Little Boys Are Made Of
 
In Huckleberry Finn, Mark Twain’s novel of American boyhood, Huck and his friend Jim hide away on an island in the Mississippi River. Boredom sets in after several weeks and, in Huck’s words, “I said it was getting slow and dull, and I wanted to get a stirring up some way … I would slip over the river and find out what was going on.” Disguising himself as a girl, he rows to shore and approaches a strange house, where a woman invites him inside.
 
During the visit, Huck attempts to thread a needle. Unlike a girl, who would bring the thread to the needle, Huck tries to do it by bringing the needle to the thread. Suspicious, the woman complains about the number of rats scurrying about the cabin, some so bold as to peek out at her young visitor. She suggests that Huck throw a heavy lead weight at them. Huck throws the weight with his arm out to one side—like a boy would—and the woman catches him out.
 
“Why, I spotted you for a boy when you was threading the needle!” she exclaims with satisfaction.
 
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Whether the tasks be threading a needle, throwing a ball, climbing a tree, or learning to write the alphabet, we often notice that boys and girls do them differently. If you have a daughter as well as a son, you can probably list a number of ways they differ in behavior without thinking about it for very long at all.
 
In Twain’s day, people would have been amused, but hardly surprised, by the clever woman’s observations about Huck. Until this century, few questioned the premise that differences in behavior between the sexes were innate—natural, desirable, and even God’s plan. Most of the world is still quite comfortable with this point of view of life.
 
Twentieth-century experts, however, have emphasized the importance of the parents’ role in bringing up their children, stressing “nurture” as opposed to “nature.” Many American parents have looked to the spoken and silent messages they have transmitted and the environment they have created for the key to their children’s behavior. Some of us have even felt guilty about our own actions or attitudes that may have encouraged aggression in our boys or passivity in our girls. If we just gave our daughters trucks and showed them how to be assertive, we reasoned, the girls would be independent like boys. If our sons were only taught concern for others and given dolls to cuddle, they would be less aggressive and more nurturant like their sisters.
 
“But it’s not so simple,” declares one mother, who tried to raise her children in a nonsexist way. “The biggest things in my daughters’ lives right now are Barbie dolls and nail polish,” she sighs. “And Jonathan—he walks like the Incredible Hulk, shovels down his food, and wants to wrestle with every boy he sees—and he’s only three-and-a-half!” Speaking of the differences between her two children, a second mother added, “When she plays with something, she wants to feed it; he wants to make it fight.”
 
For women, who do most of the hands-on rearing of young children, boys have always presented a special challenge. Their behavior sometimes seems mysterious or incomprehensible. “Why is he acting that way?” “Is it normal?” and “What should I do about this?” are questions mothers ask endlessly about their sons. “Don’t worry about it,” a boy’s father will counter. “I did the same thing,” or, “Lots of boys do that.” Because of their common sexuality, fathers understand intuitively the feelings and motivations of their sons; after all, they were once boys themselves. While it may seem an all too obvious and even trivial observation, whether you are a mother or a father affects your responses as a parent in very profound ways.
 
The Importance of Heredity
 
Students of human behavior from a variety of disciplines are now taking a second look at the importance of inborn traits. Investigators of sex differences have established that being male or female is a crucial determinant of behavior. Genetic studies show that our intelligence, adaptability, and approach to people are influenced by traits we inherit. An individual’s sex and heredity contribute to his perception of the world as well as his potential to achieve.
 
Recent findings are causing us to reexamine some of our traditional views of the sexes, including the widely held belief that males are stronger and more powerful than females. Many of us expect more of our sons than we do of our daughters, who are sometimes characterized as weak and fragile. Attitudes such as these not only have the force of custom, they are also routinely inculcated in our children from very early ages. Six-year-olds will tell you that boys are stronger and braver than girls, and that it is men who get to be the bosses.
 
However, researchers find that, despite their greater strength and power, from conception onward males are more fragile than females in substantial ways. Even before birth, maternal stress and genetic errors create more problems for males than for females. More boys than girls have trouble in school and suffer from speech and learning disabilities. When parents divorce, boys often show the emotional impact of family stress by disruptive behavior, whereas girls less often act out their feelings. In the adolescent years, boys turn to alcohol and drugs more frequently than girls do. Throughout their lifespan, males succumb to stress and disease at higher rates than females.
 
The traditional male characteristics of power, strength, competitiveness, and independence are counterbalanced by specific vulnerabilities that are present before a child is born. These contrasting qualities of strength and fragility, the techniques we use in rearing a son, and the way a boy views himself all contribute to his development. Underpinning these important variables, however, is each little boy’s unique genetic heritage.
 
Psychologist Sandra Scarr of the University of Virginia points out that a child’s individual set of genes helps bring him into contact with different experiences. As parents, our response to each child will vary. The outgoing, smiling, happy baby, for instance, causes adults to smile back, pick him up, and play. The more retiring, shy, or fussy baby makes us react far differently.
 
If you have more than one child, you are no doubt familiar with the difference in response that each of your children evokes in you. One may be the family extrovert, have a high energy level, be athletic, and possess an assortment of friends. His brother, on the other hand, may be less gregarious, enjoy playing the oboe, and have only one or two close companions. If you are, yourself, an extrovert, and enjoy being with people, you may feel more comfortable around the first of these boys. Having personality traits like your son may not, however, make it easier to raise him. “He is in motion from the time he gets up until he goes to bed,” one spirited mother says of her seven-year-old son. “I can remember being like that, and I don’t plan to let him out of my sight till he’s twenty-five!”
 
Each of us is born with what Scarr calls a “reaction range of possibilities” in a variety of areas. A child may inherit genes that are likely to help him in becoming a fine long-distance runner. If his family places a great deal of emphasis on the arts and disdains sports, however, his athletic potential may go unrealized. The boy’s rather modest musical ability may be encouraged, instead. If, on the other hand, the boy’s family nurtures his athletic gifts by encouraging his participation in sports, it is likely that his full range of talent will be developed. Opportunities allow an individual to fulfill his reaction range. By themselves, genes do not cause behavior. They make it possible for a person to develop certain strengths given the right kind of environment.
 
Genetic information is transmitted through genes, the basic units of heredity, which affect development throughout life. When we learn to walk, the onset of puberty, baldness in men, and menopause in women are all influenced to some degree by the chromosomal package we carry from conception.
 
Each parent contributes a sex chromosome to his or her offspring. Females transmit one kind of sex chromosome—always an X. Males can transmit either an X or Y. If the mother’s egg containing the X chromosome is fertilized by an X from the father, the child will be a girl—XX. A Y-bearing chromosome will produce a boy—XY.
 
The presence or absence of the Y chromosome influences a number of traits and conditions found more commonly in one sex than the other. Cleft palate, baldness, and gout occur more often in males than in females. Certain undesirable traits transmitted through the mother’s X chromosome may or may not be inherited by girls, who have the advantage of a second X chromosome from their fathers. Some disadvantageous characteristics transmitted through a mother’s X chromosome to her son, however, will be expressed. A rare, though well-known example of a sex-linked disease is hemophilia; color blindness is also a sex-linked trait.
 
For the full expression of male or female qualities, genes act in concert with hormones—chemical substances that serve as messengers to the child’s developing body. There are a number of traits that are expressed only when the proper hormones are present. Hormones help bring about the growth of beards in adolescent males and breast development in females. The sex hormones influence genital development in the fetus and then assist in further differentiation. Male sex hormones, known as androgens, stimulate the development of many masculine characteristics.
 
The Y chromosome a boy receives from his father brings about the formation of testes in the male embryo. Instead of having structures that resemble male or female sex organs, embryos in the early stage of development have what is called “ovotestes.” This tissue can develop in a male or a female way. Between six and seven weeks after conception, the ovotestes in males enlarge and eventually form the testes. Within a short time, these embryonic testes begin to produce sex hormones.