Summary: This takes place in an AU world following the episode Conversion, ignoring the cannon end of that episode. Set in early season 4, but with Beckett having survived. Major J/T.

Warnings: Contains discussion of reproductive biology (the kind as you may read in a text book) if you don't like hearing about that kind of thing, stay clear.

Spoilers: Conversion and possibly thereafter through the seasons. No real season 4 spoilers.

Note: I am not an expert in the biological subjects mentioned herein, so please do not judge me too harshly! I know there have been many similar conversion-altered John stories out there, so I apologise for my lack of originality – but is there really such a thing in scifi and fanfic? Thanks to Gater101 for starting me on this fic – it's all your fault!!

Disclaimers: I own no part of the Stargate world, I make no money from this endeavour. I only love this world so much I wish to play in it as much as I can and bend it to my Will in my own unique twisted way.

--

Doctor Carson Beckett reached for his coffee once again. He was relying on it far too much tonight, but then he realised that could be said for any day since he had arrived in Atlantis. He gulped down the last few dregs and leant back over his desk to study the computer screen.

"Doc?" The voice was soft and slightly cautious. A tone all Doctors knew well. Someone had a problem they were embarrassed about.

Carson looked up through the late dim lighting of the Infirmary to see one of his more interesting of patients, colleagues and friends. Colonel John Sheppard stood in the doorway, hands buried in the pockets of his uniform.

"Hallo, Colonel. How can I help?"

The Colonel edged further into the infirmary seeming unwilling to disturb him.

"I'm bluer." The Colonel finally answered as he came to a stop near the doctor.

"And ye want me to cheer you up?" Carson joked as he stood.

Sheppard gave him a sarcastic smile and moved with Carson further into the empty Infirmary. He hoped up onto the edge of the bed as Carson came to stand before him.

"Ye are as well." Carson remarked studying the brighter areas of blue skin that lined the Colonel's eyebrows, temples and neck. The conversion the Colonel had undergone over a year ago though reversed for the most part had left him with a few slight alterations. Carson and other experts were happy that the retrovirus was gone from the Colonel's system, but that perhaps its affects had insinuated itself into certain areas of his genetic structure beyond the ability to completely untangle them. They hadn't been worried as the suspected remaining few genes still being expressed had been limited to the unused areas of Junk DNA that all creatures carry in their genetic structure.

However, the genes that resulted in the blue shades to certain areas of Colonel Sheppard's skin had continued to be expressed even now so many months later. Carson's current theory was that these genes were linked in some part to the ancestry of human evolution and that they remained because they had always been there and the retrovirus had activated them. He was currently writing a paper on his theories, knowing full well it may never be seen by any orthodox scientists.

The still active genes did not adversely affect the Colonel in the slightest, other than the colouring, in fact he still had a slight increase in agility and his mental use of the Ancient technology had vastly improved. And Carson had heard several women remarking that the changes had only made the handsome Colonel even more attractive. Not that the Colonel would agree, his attitude towards it was reluctant acceptance. He hated that he would remain in some way marked by the whole 'Bug' situation. He hated to speak about his new appearance, telling outsiders and people back home on Earth the markings were tattoos. It was only with Carson that Sheppard felt comfortable enough to talk about his new appearance.

Carson now studied the blue areas of John's face and neck, pressing questing fingers gently against them. "The areas seem larger to me as well." He remarked and the Colonel nodded his agreement. "There doesn't appear to be any thickening of the skin. No indication of a relapse." He noted out loud, knowing the possibility was a recurring worry of the Colonel's. "How long as it been this way?"

"It's not the first time, Doc." John reported.

Carson stood back, an eyebrow raised.

"It seems to be a… monthly thing." John replied, and Carson was surprised to see a slight redness to his cheeks.

Carson pulled up a chair and sat. "There's a cycle to it?" Thinking back over the past months he could vaguely remember thinking the colours of John's skin were brighter occasionally, but he hadn't thought further about it.

"Yep, seems so. I ignored it for a while, as it goes back after a week or so, but I have realised it appears to happen every month now. And over the last few months the colouring is getting slightly brighter each month." His voice was soft in the late night Infirmary. The Colonel was a very private man and dealing with this was not easy for him.

Carson worked to not make a joke, something the Colonel would normally enjoy. "Have you noticed anything else when this occurs? Mood swings? Anything like that?"

John finally gave him a more usual glare. "No, Doc, it's not that. Though, I have noticed I have more energy and that smells and things seem more intense."

"Mmmmm. Interesting." Carson sat back an idea occurring. "I think it may help if we spoke with another specialist."

"Who?"

"Doctor Bays."

He watched as John struggled to place the name before realisation hit him. "The vet guy?!"

"Doctor Bays is a specialist in all forms of animal life. He's been studying some particularly interesting creatures on several worlds. I think his knowledge of animals and particularly reptilian and insect life could be helpful here."

The Colonel looked down and sighed. "I can't believe you want me to go to a Vet!"

"No, no. I just think his more extensive knowledge may help us. He has done a lot of study on the Wraith, including the Iratus Bug. I think he may be able to help us."

John considered it for awhile. "Okay, but you tell no one about this. I mean it!"

"I promise, Colonel." Carson worked not to laugh. It was difficult, especially as the Colonel looked rather like a forlorn puppy right now; a blue forlorn puppy.

--

Doctor Bays sat back, a finger pressed to his chin. "Mmmmmm. Interesting."

John rolled his eyes. "That seems to be the consensus."

"And you say you have more energy and your senses are sharper?" Bays asked for clarification. John nodded. "And it happens every month."

Carson leant in. "All the tests I've run are normal for him, though there is an increase in testosterone in his system."

"Well it obviously implies a sexual cycle of some kind." Bays replied.

John widened his eyes at that, said so casually.

"It is strange though, there isn't usually a male cycle in humans or in Wraith as I have found. In most species a male responds to the female's cycle."

"Excuse me?" John asked, ignoring Carson's struggles to not look amused.

Bays leant further back in his chair, his finger now tapping against his lips. "The female sends out certain signals; whether they be scent or behavioural. The male responds by displaying." His hand came up and waved towards John's head and neck. John felt a blush adding more red into the mix. "The female then selects her choice and mating occurs."

John tried not to grimace at the natural history lesson. "You make me sound like a bird of paradise shaking my tail feathers."

Carson coughed over a laugh, but John smiled over at him. Carson relaxed somewhat. Hell, no adult could usually keep a normal face when discussing this subject matter on a normal day.

"I believe this is something similar." Bays continued. "It happens to a certain degree with humans, though not as obvious as with other creatures such as your birds of paradise."

John looked shocked and Carson jumped in. "T'is true. There is research indicating that whilst women are ovulating, their male partners find them more sexually alluring. Women's features become more symmetrical and attractive, as well as the possibility of pheromone release."

"O-kay." John uttered.

"You did say that you are more sensitive to smells." Bays remarked. "Do you have an increased libido as well?"

John worked to stop the second blush in as many minutes. Perhaps it was a side affect of this reaction. "Kind of, but it dies down after a day or so." He admitted reluctantly. He refrained from mentioning the steamy, needy dreams that plagued him for the whole week.

"It makes sense then." Bays remarked with a flourish. "However," he frowned in concentration, "that doesn't quite track; as I understand it Doctor Beckett the female military staff here are on the contraceptive pill?"

Carson nodded seeing where this was leading. "Ai they are, which means they do not have a cycle. However, not all the women on this base are military personnel. And the Colonel has regular contact with off-worlders."

John looked from Carson to Bays and began to worry this was heading towards the same conclusion he had already suspected.

Bays continued to frown. "But, the Colonel is experiencing this as a clear monthly cycle. If he were being influenced by any and all females that came near him whilst ovulating-"

"Can you stop using that word, please?" John cut in.

Bays looked up at him and frowned further, the crease cutting deeply down the centre of his forehead. "Alright, any female who was near you during the correct time would affect you. That would mean you would likely to be constantly reacting to all of them and having this reaction much more often."

Both Carson and Bays looked up at him expectantly. John looked away sheepishly, realising that his own theory had indeed been correct. He waited for the Doctor to say it out loud.

"So, that would indicate there is only one female on the base to whom you are reacting." Bays concluded out loud.

Damn it.

--

TBC