"She's right, you know."

John didn't even look up from his paper. "Who?"

"Donovan."

John looked up in surprise. He had never expected those words to come out of Sherlock's mouth. "I'm sorry, could you repeat that?"

Sherlock gave John one of his 'don't-be-an-idiot' looks. "You heard me."

"Right. So, what is she right about?"

Sherlock sighed in exasperation that John wasn't following his alarmingly simple thought process. "That I'm a sociopath. She says 'psychopath', but she means 'sociopath', of course."

"Ah." John went back to reading his paper, not interested in how the rest of the conversation was going to play out.

"I mean it."

"Okay." He was determined not to rise to Sherlock's bait.

"You're a doctor – I'm sure you know the symptoms."

John spoke from behind his newspaper. "I'm a doctor, Sherlock, not a psychologist."

Sherlock fought the urge to roll his eyes. "I'm sure you know anyway, John. Do you need me to list them for you?"

"That really won't be necessary." Even as John said it, he knew that it was pointless. Sherlock was going to do it anyway. He was right.

"While the term is loosely defined, the common public", he spoke the term with derision, "tends to use it as a synonym for Anti-social Personality Disorder. The symptomology is slightly different depending on what method of diagnostics you use, but there are some main similarities."

John tried to force himself not to listen, because really, it was far too early in the day to be listening to Sherlock's babbling, but as usual, he was unable to tune the detective out.

"Sociopath's have a tendency to break the law-"

"Only when it suits you", John chimed in.

Sherlock continued as though the other man hadn't spoken. "A complete lack of empathy and understanding of other people, including the use of deception and manipulation, and a distinct lack of guilt or remorse-"

"Does it count if you don't know you're supposed to be remorseful?"

Sherlock shot a glare in his direction. "Obviously. There's also impulsivity, irresponsibility, and a lack of regard for one's safety."

John didn't argue with any of those. He assumed that the conversation was over, but Sherlock kept talking.

"Also, according to Theodore Millon, there are five different subtypes of the disorder. The first, covetous, doesn't apply to me. The second, reputation-defending, involves narcissistic tendencies, and that doesn't apply either."

"Really." John's tone was flat, making his sarcasm unmistakeable, even to Sherlock.

Sherlock snapped at him. "I am not narcissistic. My intellect is far beyond that of the average person, and that is purely factual information. Need I go into the definition of narcissism for you as well?"

"No, no, that's alright."

Sherlock continued his speech. "The third type is risk-taking, which includes histrionic features, and really, let's not get into that."

John didn't argue.

"The fifth type, malevolent, doesn't really apply. Despite what many seem to assume, I'm not a particularly sadistic person, nor am I paranoid."

"Wait. You skipped four." Such a blatant mistake didn't seem like something Sherlock would do.

"Yes, quite intentionally."

John ignored the weight of Sherlock's stare and stayed silent, waiting for the man to explain himself as John was sure he would.

"The fourth type is nomadic." Sherlock paused, waiting for John to put the evidence together.

John said nothing.

"Nomadic anti-social individuals are characterized by avoidant and schizoid traits."

"Not a psychologist, Sherlock."

"Avoidant individuals make a point of not making relationships with others. Schizoids are basically the same."

"Oh." John still didn't know where Sherlock was going with all of this. "And?"

Sherlock looked at his flatmate with frustration. "Isn't it obvious?"

"No, it really isn't."

"I find that I most closely relate to the fourth subtype, the nomadic anti-social."

John nodded and went back to his paper. He had only read three lines when he realized that Sherlock was still staring at him intently. "Alright, what else?"

"There's a problem."

"There is?"

"Yes. While I fit the subtype fairly well, there is one symptom, specifically of the schizoid traits that I don't quite fit."

"Oh?"

"Yes. Schizoids are known for having little to no sexual desire for other people."

"Oh." John tried again to go back to his newspaper before Sherlock's words sunk in. "Oh", he said again in understanding.

Sherlock ignored John's exclamations. "But I don't seem to manifest that particular symptom. Or rather, I used to in the past, but I find that changing now."

John simply stared at him, unsure of how to respond to this new information. He had always known that Sherlock didn't understand the bounds of what was considered appropriate conversation, so he didn't know why he was surprised that the detective would bring this up.

"Since I fit all the other traits, I don't quite understand why it is that I find myself so attracted to you."

John blinked. "Pardon?"

"Don't play dumb, John, you have enough of a lack of intelligence without the acting."

John was too busy reeling from that last statement to be insulted. "I'm sorry, did you say you were attracted to me?"

"Yes, of course, wasn't it obvious?"

"No."

"And you're attracted to me too, of course."

"Wait, I am? Who said that?"

"Must I really explain my reasoning to you? You stare at me when you think I'm not looking, and when you do, your pupils are dilated. You seek approval from me and become pleased on the rare occasions when I give you praise, even though you don't seem to care nearly as much if the praise comes from other people. You agreed to move in with me after knowing me for only one day, and you make excuses to be near me as much as possible. It's common that you have an erection-"

"Enough, Sherlock."

"It's all really all quite obvious, as I said."

"What's your point?"

"I'm sexually attracted to you, which is quite odd. I don't understand. I need to find out why, which means experimentation needs to be done. Since you're attracted to me as well, I assumed that you would be amenable to the idea."

"You're asking me to have sex with you." John's tone was unbelieving, but Sherlock, predictably, didn't pick up on it.

"Yes, for the sake of science."

It really was too early for this. "You do realize that this isn't the reason most people have sex."

"Isn't it? Don't bother giving me all the lies about emotions and intimacy, because it's all blatantly untrue. People have sexual intercourse because they find themselves sexually attracted to one another and it brings them physical pleasure."

John gaped at him. "Yes, well."

"It's very simple, John. It's mutually beneficial to both of us."

John had no idea what to say to him. His newspaper was still in his hands, but it sat unread, and John had actually forgotten he was even holding it. Instead, he gaped at Sherlock as though he had grown a third head, which he might as well have.

Sherlock continued as though he hadn't just propositioned his flatmate in the least romantic way possible. "So, I'll meet you in my bedroom in 10 minutes? I need to prepare first."

"But."

"I only said my bedroom because it's a more controlled environment and I'll be able to collect more valid data there. But, if you really insist, we could use your bedroom. I'll just need more time to prepare things. Would 20 minutes be acceptable?"

"No, that isn't-"

Sherlock stood up and began to walk to his room. "Right, then. 10 minutes, John. Don't be late."

John sat alone in the living room, unsure of what had just happened. Surely he hadn't just agreed to have sex with Sherlock, had he? There was no way that had happened. Maybe he was dreaming? It was his day off work and he had planned to sleep in today. He looked around and pinched himself. It hurt. So, he was awake after all. But that meant...He smiled to himself. It seemed that he had just agreed to sex with Sherlock after all, no matter how little choice he had been given in the matter. Really, his lack of input wasn't all that unusual at all. He glanced at the clock and began to walk back towards Sherlock's bedroom.