Do you have a reference for this? I don't think he mentions anything like this in his "Thru The Bible" commentary series. I'm not disputing you, I've just always liked J. Vernon's folksy pastoral style and I'd be interested in reading about this further.
I heard his through the Bible sermons on the radio quite a bit and I remember that sermon specifically, though I don’t remember the chapter he was covering—probably Genesis. He was very adamant about “multiply and replenish” not applying to New Testament believers. (It would be interesting to see how many children he had.)