Image Chastain at a Super Bowl party last month. Credit... obin Marchant/Getty Images for Fanatics

Q. Did you tell your son?

A. My son and I had the conversation this morning. I said, “I just want to let you know that we’re going to donate my brain to science.” And he goes: “That’s weird, Mom. Why would you do that?” And I could see he was thinking like, “Won’t you need it?” I said: “This is a long time from now, Jaden. You don’t have to worry about it.” And he goes, “All right,” and went back to what he was doing. But I explained to him that if you cut a tree in half and look at the rings, it will tell you the story. If there are irregularities, scientists can say, “Oh, this happened,” and they can tell when it happened because of the rings. I explained to him that if there is a way when they dissect my brain that they can say, “O.K., at the age of 9, we see this,” maybe they haven’t had that information before. That would be really helpful, I’d think. It made it easier to say yes.

Q. You estimated that there were “probably a half-dozen times” in your career that you shook off likely concussions from heading the ball. Have you experienced symptoms that concern you?

A. There are definitely days when I turn a corner and I’m like, “Why did I come into this room?” I have definitely, from time to time, thought, “Hmm, I wonder if this is connected to the past 40 years of playing sports.” Soccer wasn’t the only thing I played. It’s crossed my mind. I do wonder about the ramifications over the next 20 years when I should be fully functioning and still doing things I like or want to do. I try not to get hung up on those things, because it doesn’t really matter at this point. You just don’t know.

Q. Have you had this conversation with other national team members?

A. I haven’t had conversations with present players. I’ve had conversations with Cindy Parlow, Kristine Lilly, Mia. I don’t really think it’s a topic of conversation at this level. I think Abby Wambach — I’m trying to get her to come onboard because I think she will be an interesting brain study, decades from now, as the player who scored 75 goals with her head and probably put her head into places, like Michelle Akers, where they probably didn’t belong. How many times did she hit her head on the ground after being run over by somebody?

A lot of us have kids now, so I think the conversation today is much different than it would be 15 years ago. That’s part of it. If I don’t want my son doing it, I can’t be coaching somebody else’s son to do it. My teams, my young team, U-10 Santa Clara Sporting, will not be heading the ball. And if it means giving up a goal, that’s O.K. Or we don’t score one, no problem.