If it's any help, I've managed to get a son while flying night freight (4-5 nights a week--when ever did I find the time!), a daughter while flying longhaul, and am now awaiting the arrival of the second male offspring, while now flying shorthaul. This at regular 4 year intervals.
Of course, these are the only one's I know about.( NO dear, I haven't slept with a hostie, not one wink
)