Davis is the first girl to throw a shutout (when a single pitcher pitches a complete game and does not allow the opposing team to score a run) at the Series.

Mo’ne Davis, the ace of the Taney Dragons in the Little League World Series, spoke fluently about “release points” and the art of confronting batters who were uncomfortable hitting the ball to the opposite field. It was advanced stuff for any pitcher, let alone one who was 13 years old.

Davis, having captured much attention in recent days with her blazing fastball and her waist-length braids, had already pitched one shutout in the tournament. She throws with a fluid motion —and she throws hard, her fastball topping out at more than 70 mph. For Little League hitters who face her from just 46 feet, her heater is the equivalent of a pitch with a velocity in the low 90s on a larger, big-league diamond. The ball is a blur as it leaves her right hand.

“She’s pretty special,” said Dr Jeremy Ng, a sports and performance medicine physician at the Children’s Hospital of Philadelphia.

Her specialness is clearly formed by mental and physical gifts. But one of her advantages may come as something of a surprise: her sex.

Players in the tournament range from ages 11 to 13 — namely the onset of adolescence and all the physical transformations that follow. But not all change is equal, and girls generally get a two-year head start on their growth spurts.

Consider, for example, that the average 12-year-old girl is slightly taller and weighs more than the average 12-year-old boy, according to data compiled by the Centers for Disease Control and Prevention.

At 5 feet 4 inches, Davis is more than 3 inches taller than the average 12-year-old boy. In fact, her height would put her in the 50th percentile of 18-year-old women. Being tall and lean for her age allows her to generate additional velocity on her pitches.

Davis also appears to have good flexibility in her shoulder, a likely product of throwing overhand from an early age. Dr Ted Ganley, the sports medicine director at the Children’s Hospital of Philadelphia, said the repetitive motion of throwing a baseball can cause a structural change in the shoulder as it develops, allowing for greater rotational flexibility.

So if Davis is capable of throwing 70 mph now, what is to prevent her from throwing 90 mph in a few years?

One obstacle could be that Davis has already developed physically. In other words, she will probably not get too much taller, whereas many 12-year-old boys are prepubescent and have yet to begin their growth spurts.

Girls, Ng said, often begin puberty at around 11; for most boys, it begins two years later but lasts twice as long, which helps give them 1 1/2 times as much lean body mass as girls. “It’s not really about what she isn’t going to be able to do,” Ng said. “It’s what the boys start doing.”

History suggests that Davis may be nearer the end of her baseball career than the beginning. Only 1,259 girls played high school baseball nationwide in 2013, compared with 474,791 boys, according to the National Federation of State High School Associations.

There are no baseball teams solely for girls. And those who seek to play varsity competition sometimes face resentment for taking a male player’s roster spot — not to mention the hidebound notion that baseball is for boys, not girls.