Inspector Gregson was undoubtedly speaking of a hypothetical babe unborn, but it suddenly makes me wonder about everybody else in the Canon: Were any of them never born?
Some would say that many of them weren't, and sprang fully-formed from the mind of some almighty creator whose great powers of imaginative detail brought them to life. But many had places of birth: Pershore. New Jersey. London. Greece. Posilippo. Brazil. America. And many had birth years: 1846. 1856. 1840. 1845. (This makes it only possible to do Chinese Zodiac calculations on those four, as far as astrology is concerned, and imperfectly at that: Was Irene Adler truly born in the year of the Horse? No wonder the guys at the stable liked her! Moran in the year of the Rat? Sounds right, he did crawl into a sewer quite handily to chase a tiger once.)
Birth in the Canon seems to define a person, as the phrasing hints at national stereotypes. "Brazilian by birth." "Greek by birth." Perhaps it's national pride, if like Mr. Melas, one is making the statement about one's self. But when Holmes says of Reginald Musgrave, "Something of his birth place seemed to cling to the man . . ." one starts wondering if he might be hinting at smell or something else less than complimentary.
Birth judgments occur: Professor Moriarty had a "good" birth, but Fitzroy Simpson had an "excellent" birth. What's an excellent birth? Personally, I picture Fitzroy strutting out of the birth canal with a top hat and cane, singing "Hello my baby, hello my honey, hello my rag-time gal!" but I'm sure that's just me.
Others seem to be born with a special quality.
Mary Fraser was "born for all that is beautiful and dainty." What all those things are specifically is a good question. Tiny houses and flowers come to mind. Von Bork was a "born sportsman." McMurdo was a "born boon companion."
Poor Inspector Bardle of the Sussex constabulary was treated as a farm animal, as he was "born and bred." Wouldn't "bred and born" be the proper order? Or was Bardle raised to manhood and immediately set to stud by wicked Sussex eugenics proponents?
John H. Watson perhaps had it best, as he was told by one very smart fellow: "My dear Watson, you were born to be a man of action."
And with all of the data above, however, only one person in the Canon has an actual birthday. James Armitage, who celebrated turning twenty-three with chains on, below-decks on a prison ship, and working out that birthday's date is still a challenge. But we at least have evidence that he was born.
Otherwise he might run afoul of the villain Wilson Kemp, who liked to tell people "You had better never have been born." So perhaps there was a secret cabal of those who had never been born in the world of Sherlock Holmes, and if you were a member, you got special privileges from men like Wilson Kemp. They were certainly must not have been good folk like any of those mentioned above.
Or those of us who enjoy a good birthday celebration. So when your birthday rolls around, give Wilson Kemp the finger and accept a big "HAPPY BIRTHDAY!" from me. You must be one of the good ones!