Comment Oops (Score 5, Informative) 284
It seems I may have jumped the gun on this one. My bad for being such an easy mark of sensationalist pop science headlines.
If the older child is a boy born on Tuesday, there are 14 equally likely possibilities for the sex and birth day of his younger sibling: a girl born on any of the seven days of the week or a boy born on any of the seven days of the week.
One of those 14 possibilities is another boy born on Tuesday. The exclusion mentioned in the next paragraph is to avoid counting that case twice.
Due to lack of disk space, this fortune database has been discontinued.