"He does care," Lois agreed. "He's spent his whole life thinking he was alone here, and then suddenly you show up and... you're his only tie to a family he's never known. You gave him something he thought he'd never had, and the love he feels for you - there isn't a thing he wouldn't do to see you happy and safe. That's all."
Lois wasn't surprised. She had first started learning about sex when she was seven. Kara might have grown up on a different planet, but some things couldn't be all that different. Even if they were, this was Metropolis and high school gave kids a quick education in a lot of things that weren't on the standard curriculum.
"Careful is important," she agreed. "Of course. And as far as I've been able to tell, no, pregnancy might not be an issue. We don't know for sure, but so far," she gestured with one hand. She and Clark hadn't made an effort to prevent starting a family, but in three years, they'd had no luck in that area.
"Disease? I really couldn't tell you one way or another, and frankly, you're stronger than any supposed axe-weilding serial killer out there. The big worry we would have with you is that you'll get your heart broken." Lois frowned a little. "People can be such amazing assholes sometimes, and when you throw in something like sex, it gets so much more complicated. For some people - mostly guys - it can be really simple. Sex is just sex. For others, sex is about emotions and connections and if everyone isn't on the same page, or if someone's lying, or one person cares more than the other... people get hurt."
She pursed her lips, thinking about it. "When I was fifteen, I slept with this guy. It was my first time, and he was a soldier on the base my dad was stationed at in New York. He was... older. It didn't really matter to me; I'd grown up on bases, so all these guys were like my brothers, or my playmates, you know? And my dad and I were always fighting, this guy listened... anyway, he bragged about it to his friends, and somehow it got back to my dad. The guy was discharged and sent home and every guy on the base blamed me. I was the enemy who'd gotten one of their brother's in trouble. And my dad?" Lois snorted. "He never said a single word to me about it. I would have thought he didn't know at all except he wouldn't even look at me, either, and he personally handled the discharge."
This was one of those times she wished she still smoked, but Lois smirked. "So the lesson I learned, was 'don't trust anyone' - but Clark has taught me something else. I ran away to Metropolis right after that and looked after myself right up until I met your cousin and fell in love with him. So that's what he's worried about. Your heart."
Kara's question made her laugh. Loudly. "Yes," Lois nodded. "Yes, Clark knows about sex. He can't at all discuss the subject, and before me his knowledge was largely... academic, he has received a decent practical education since then. And in case you're wondering," she lowered her voice conspiratorially. "No, we didn't wait until we were married. And that was by complete mutual agreement, not just because of me."