Final answer:
The condition that affects girls and boys equally in early to middle childhood is D. Overweight/obesity, with both genders being similarly susceptible to this health issue.
Step-by-step explanation:
The condition that affects girls and boys about equally in early to middle childhood is D. Overweight/obesity. Although the exact trend may vary regionally, both sexes are at similar risk of becoming overweight due to factors such as dietary habits, physical activity levels, and socio-economic conditions. In contrast, Autism spectrum disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) are more prevalent in males. ASD is four times more prevalent in males than females, and ADHD also shows higher prevalence in males. Learning disabilities encompass various disorders, such as dysgraphia, dyslexia, and dyscalculia, and can manifest in both genders, however, they do not strictly relate to the prevalence of overweight/obesity patterns in childhood.