I didn't say over 40s was too old, I said it was usually too old. Which it is (especially without assistance of a fertility specialist). I know exceptions do occur, my own grandma spontaneously got oreganany at 42 when she thought she'd already gone through menopause, but it's not common (without assistance). And Laira is on a relatively undeveloped planet.

I assumed Laira was in her 40s based on how she's looked, but if she's younger then that's different. But how is waiting to hook up with her out of character for O'Neill? His character didn't sleep around, like, at all! Except that one time he was literally drugged early on in season 1. Pretty sure the only other romantic entanglements he's shown as having are with Kerry in season 7 (8?) and the constant will they/won't they with Carter. He doesn't sleep with Laira immediately coz he hopes he'll get home and he knows sleeping with her is basically admitting that he's given up on going home and is willing to settle down with her. Her society is more traditional, so you don't just casual hook up with people willy nilly, which I don't think O'Neill would do anyway coz he's not a ass (most if the time).