There is one weak point for boys. Boys tend to be careless. So they want to play, play often and play more. They want to win. They make a lot of moves that are not sound or are really bad. They have been making a lot of mistakes, much more than girls. But in the end, they learn from their mistakes, and make much faster progress.
On the contrary, girls tend to be careful and think thoroughly. They don't want to make mistakes, which is considered stupid. And they make less mistakes. But they also learn less, and progress slower. This is in fact the biggest mistake girls are making.
Learning chess is like a lot of other activities. You have to take risk. The more risk you take, the more you will learn. That's why your child should take challenges, playing up and playing against adults.
As a beginner, my daughter started with King's Gambit. I also encourage my students to pick up the opening. It trains them to be more aggressive and take a lot of risks.