I've had the opportunity recently to meet with and speak to a number of bloggers based in London. I've formed the opinion in almost all cases that these men do not have any children.
Considering that most of the people I've seen are on the "better" side of 30, it may well be that this cohort will not be reproducing at all. The people in question are generally well-educated, generally straight, and generally employed gainfully.
Perhaps blog-writing isn't correlated with having a relationship, or we are seeing the evolution of new libertarian priesthood?