Q: My ex-husband has our 3-year-old son from Thursday through Saturday, every weekend. When I hand him over to his dad, he’s fairly well-behaved, but when I get him back, he’s disrespectful and defiant. It takes a day or two to get him back on track. I work very hard to discipline consistently, and it seems his dad unravels everything I accomplish.

A: In the attempt to be fair to both adult parties, divorce-court judges often make rulings that are distinctly unfair to children. The sort of back-and-forth custody arrangement you describe is going to be very disruptive to most 3-year-olds. In fact, having to move households every few days would be very disruptive to most adults. Unfortunately, when parents’ divorce, children don’t have attorneys arguing on their behalf.

The problem is compounded by fathers who are nothing more than large playmates when they have their kids. This makes it difficult for their children to transition back to mothers who expect obedience and impose structure. Needless to say, this is no picnic for the mothers either.

The only solution is for you to stay the course. Even though you’re in a “two steps forward, one step back” situation, continue to discipline consistently and with purpose. Eventually, your efforts will pay off.

Q: My 5-year-old seems to have difficulty paying attention and is in constant motion when I try to teach him to read or write. That said, he can sit and watch a movie or build with Lego blocks while following the instructions. Is this ADHD or just him being bored and not liking the activity?

A: I can’t make a diagnosis in a newspaper column, but I can tell you that some degree of inattentiveness and “hyperactivity” is characteristic of young boys. That tendency is aggravated when adults force them to participate in activities they’re not interested in. For instance, it may well be that your son is simply not developmentally ready for academics. That readiness emerges in girls before it does in boys, who tend to be more inclined toward activities involving motor skills; thus, your son’s interest in Lego sets.

According to good research, other factors that may contribute to excess activity and problems with attention span include watching excessive amounts of television, playing video games, and improper diet. Your son sounds like a typical 5-year-old boy to me, but if you have any doubts, I strongly recommend a consultation with a child psychologist.

A psychologist, Rosemond answers parents’ questions at www.rosemond.com.