"Alright Yin, I'm gonna quickly grab lunch," Tom said as he got up from the control screen. "Keep an eye on her. Remember what's supposed to happen: The alien is hermaphroditic, right, so the sperm and the eggs are all mixed inside of her right now. The T-7 receptor in the egg's membrane is very temperature sensitive, and will only be activated at body temperature - 37 degrees."<br/><br/>"Is that why you can't use sick girls for this?" Yin asked.<br/><br/>"That's right, because even if they have the slightest fever the temperature gets all screwed up and fertilization can't occur. Do you remember the exact mechanism?"<br/><br/>"Yeah. Humans and Tridactylites secrete very similar immunoglobulin G in their intestinal mucus, and this immunoglobulin G can bind to the T-7 receptor. I don't remember the exact details, but the general idea is that then the conformation of the T-7 receptor changes into either the alpha or beta form, the alpha form being dominant and infertile. The beta form occurs at a low percentage, and only at 36-37 degrees C. This allows the sperm to bind to the receptor, at which point fertilization can occur."<br/><br/>"Very good. And like you pointed out, Tridactylites also have this immunoglobulin G, and they're the natural hosts for Wartrolls on their native planet. The trouble is they're no good for breeding because they inevitably die from the insemination process, and often go cold before fertilization can even take place. In fact, that's the real reason we're using a human host; we think a human may actually survive this process better, and even be reused many many times."<br/><br/>"So theoretically you could use a male or a female, because it shouldn't matter right? They have the same immunoglobulins, right?"<br/><br/>"Yeah, we could and we might give it a shot in the future, but we're using a female because they are better prepared for that kind of pain and therefore stand a better chance of surviving the invasive insemination process. Also, they're more efficient because they can give birth through the vagina as well as through the mouth and anus. Remember? Cervical mucus has immunoglobulin G as well."<br/><br/>"When they're not ovulating," Yin pointed out.<br/><br/>"That's right. Yeah it's hard to get all the variables to line up perfectly."<br/><br/>"I can't believe you expect her to survive all this."<br/><br/>"Well yeah, the birth-giving will be the real test of her usefulness as a breeding host in this project. And we have to test all the candidates on the same girl, because it's so damn hard to get a girl who is perfect for all the variables. We might have to make genetic clones of her if she survives."<br/><br/>"So then what happens if she dies and you still have untested species?"<br/><br/>"Well, the way this is organized is such that she will be impregnated by the species in increasing order of death risk, the highest risk being at the very end. That way if she dies we'll know what the limit is."<br/><br/>"How do you know which has the highest death risk?"<br/><br/>"We rank them based on various estimates. I know, it's pretty subjective. Hey, I didn't come up with this project, don't look at me."<br/><br/>"So what happens now?"<br/><br/>"Now? You sit here and watch the screen. The zygotes will grow extremely fast, so you should see her belly start churning in twenty minutes. The babies actually secrete a peptide which will make her epithelial cells more elastic. This will theoretically prevent her from bursting as they grow and stretch her out. I'm sure I'll be back by then, but you might start seeing them churn around inside of her. Some runts might even slip out of her mouth before the incubation is complete. In approximately 40 minutes they'll dissolve the sap and start crawling out of every orifice. That's the most critical part because they get excited and might actually rip her open. I'll be back here by then though, don't worry."<br/><br/>Tom patted the post-doc on the back and ran to get his lunch.