Firstly, and foremostly, when taking photographs of your darling son(s), make sure you have him/them remove his/their hand(s) from his/their crotch BEFORE hitting the shutter button. "Duh!" you say? I forget this simple tip more often than I care to admit.
Secondly, put your manually selected autofocus point (you guys do manually select your autofocus points, don't you? If not, immediately read up on these in your camera manual and start using them!!) on the thing upon which you want to focus. In this photo, it would have been nice if I had focused on either my darling husband's or my darling son's happy, delighted face, not my neighbor's white porch bannister in the background.
So, to recap: hands off the crotch and focus on the right spot. End of lesson. No need to thank me.