Free Rules for 50/50 Chances by Kate McGovern Page A

walk signal appears, counting down in white digits from thirty seconds.
    â€œYou don’t ‘catch’ a genetic disease,” I say. “That’s the point.” He shades his eyes from the sun with one hand, just surveying me, while the walk signal drops down to twenty seconds. Of course, he knows you don’t catch a genetic disease. “I mean, obviously. Well, you were kidding. Okay, I’m shutting up now.” Nice one, Rose.
    But he just laughs again, the shoulders going, and somehow I feel sort of okay being the biggest dork on the planet. Like I don’t have to pretend I’m anything but.
    â€œOkay, HD. Well, in that case, please don’t experience the effects of epigenetics and have a mechanism in your present environment effect changes to your genetic expression. Better?”
    Now I’m grinning. “Better.” He grins back, then turns to jog across the street before the light changes again.

Six
    â€œSo? Details, please. The date. Tell me everything.” Lena leans across her desk to whisper in my face when we sit down for AP Calculus first period Monday morning. She looks like a proud mother who’s about to ship her kid off to college.
    â€œAlso, what do you think happens if a guy with the gene for sickle cell and a girl with the gene for Huntington’s make babies?” Lena muses. “Do you think those gene mutations would magically cancel each other out and you’d have perfectly healthy children?”
    I roll my eyes at her. “Okay, first of all, you’re incorrigible. Second of all, he doesn’t have sickle cell, his sisters do, and anyway, that is a totally scientifically unsound theory. And third of all, it wasn’t a date. It was ice cream and conversation. Very civilized. You should try it.”
    At the front of the room, Mr. Petrilli is writing out some warm-up problems involving standard deviation on the white board. I like Petrilli; we all do. He’s been teaching here forever. Bowling ball head, thick Boston accent, and he takes three days off every April to go down to Red Sox spring training. That, and he’s known for using Mrs. Petrilli’s baked goods in class from time to time. I still don’t understand how Rice Krispies treats are related to the derivative, but it doesn’t really matter.
    â€œCome on, give me a clue,” Lena whispers, leaning a little closer as she opens to a clean page in her notebook.
    I start jotting down Petrilli’s warm-up problems. “He goes to Barrow.”
    Lena’s face contorts instantly, like she’s just bitten into a sour gummy. “Seriously? Ick!”
    â€œNo, he’s cool. He made a joke about it. He’s funny. And smart.”
    â€œFunny and smart,” Lena says triumphantly, nodding. “Like you.” She gives me one of her huge toothy fake grins. Lena acts like a goof a lot of the time, and she can sometimes sound ditzy, but she’s actually one of those effortlessly smart girls who gets A’s on everything without even trying that hard. I’d probably hate her if she hadn’t been my best friend since forever.
    Petrilli clears his throat and launches into today’s lesson: “Ah-right, let’s talk about stand-ahd deviation.” I relax a little at the excuse to stop thinking about Caleb and set my eyes on the board.
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    But then I have no choice but to think about him, because he disappears. No text messages, no IMs or Facebook chats. He doesn’t even respond to the Teens with Bad Genes link I send over. By the middle of week two with no sign of him, I’m convinced that he’s vanished because he’s realized that he made a massive mistake by hanging out with me.
    â€œMaybe he thinks I thought ice cream was a date-date? And now he feels awkward about it?” I ask Lena over the phone when I should be finishing my English reading.
    â€œIf that’s true, he’s super