The first call for a writing conference between student and instructor came in the 1890s in the university setting (Lerner, 2005). Education writers called for differentiated instruction to avoid mass-producing mediocrity. The writing conference is inherently differentiated. In that one-on-one context, a teacher can extrapolate the student's readiness level and interests. In that individualized setting, she can also completely extinguish a child's natural gift for story-telling, squelch his or her zeal to imagine and create. 

My first writing conference came in the 1980s. My third grade teacher accepted my Prince and the Revolution-inspired massacre where everyone bled purple. She also knew me well enough not to fear any psychological aberrations. She understood that I wouldn't, couldn't write about rainbows and ponies. Almost twenty years later, she introduced me to the Greater New Orleans Writing Project. 

Lerner, Neal. (2005). The teacher-student writing conference and the desire for intimacy. College English, 68(2), 186-208.