When did smoking during pregnancy first become taboo?

I've tried Googling it, as you may suggest to me, and all that came up was the effects of smoking during pregnancy, none of the history behind it. I know this was taboo in the 1970's, but when? Basically, when was the first baby diagnosed with health problems, and physical and mental disabilities due to the mother smoking while pregnant born.

I'm just think of the protagonist of my last completed novel, whose mother smoked heavily while pregnant with him and his three older sisters. The sisters were all born in the 1960's, all healthy and normal, while the protagonist was born in June of 1970 with a serious form of cerebral palsy. I just want to know if this family situation would be realistic. Thanks.