Here's a quote from the esteemed columnist:
If one claimed, in the manner of Albert Schweitzer, that all life deserved moral respect, then plants have rights, and it might turn out that we would have little if anything to eat. And if one were consistently pro-life, one would have to show moral respect for paramecia, insects, tissue excised during a medical operation, cancer cells, asparagus and so on. Harvesting carrots, on a consistent pro-life hypothesis, would constitute something of a massacre.
Two words: Oh. My.