'Mothers and Sons,' which opened on Monday night at the John Golden Theater in an impeccably acted production directed by Sheryl Kaller, is wrapped in a sense of urgency that paradoxically saps it as a drama. It wears its significance defiantly and a bit stiffly, rather as Ms. Daly's character, a Dallas matron visiting Manhattan, wears the big, blocky fur coat in which we first see her...It is, in essence, a debate play with fraught emotional underpinnings, and it doesn't avoid the stasis of that genre. It also tends to sabotage its potential to move us by making the debate, rather than psychological credibility, its first priority...The performers are skilled enough that we don't hear the sound of gears stripping. But they can't entirely justify their emotional U-turns, nor keep at bay our sense that we are following a menu of subjects that must be covered before the evening's end.