"Sexual monomorphism? Does that mean they're hermaphrodites? Like slugs?"

"No Captain. The Coridan people have two sexual genders, as the majority of known species do for the benefit of genetic variation. However the outward appearance of each gender is indistinguishable."

Bones leant forward to pick up where Spock left off.

"Half the population produce sperm and half produce eggs, Jim. Just like most everybody else."

"I believe I sufficiently explained that Doctor," Spock noted.

Kirk swivelled in his chair thoughtfully.

"But how would a man know who to approach? I mean, if they're indistinguishable?"

"They are physically indistinguishable," Spock explained promptly, "but culturally very different. The males and females behave in a different manner and dress in an appropriately representative way. There are also strict taboos on acceptable occupations and activities for each gender."

As Jim pondered this rather intriguing prospect, McCoy felt his patience waning.

"How in blazes did we get onto this topic anyway?" he demanded.

Spock raised an eyebrow as he replied.

"The Captain had informed us of Starfleet's priority mission to supply medical aid to Coridan. I was attempting to explain the challenges this would raise due to their sexual monomorphism."

"Challenges? What challenges?"

"As you doubtless remember, my father was instrumental in gaining the Coridan system admittance to the Federation. In exchange for mining rights to dilithium crystals the Federation pledged to supply both defensive and medicinal aid. As we have yet to install any permanent bases, the Coridanites would be well within their rights to cancel their agreement if we fail to assist them in their first plea for help."

"Yeah, I doubtless remember that Mister Spock," McCoy said. "That doesn't explain the challenges you mentioned. Nor the relevance of their sexual monomorphism."

"It is necessary to understand the challenges," Spock continued blithely. "As new members to the Federation, the Coridanites have yet to adapt to other worlds' ways. Given the immediacy of their emergency, there is not time to negotiate the necessary concessions."

"And what's that supposed to mean?" Bones huffed.

Kirk rejoined the conversation.

"It means Starfleet has ordered us to render assistance – however we must. The Coridan system is too important to jeopardise by being culturally insensitive."

McCoy looked between Spock and the Captain. He felt a sinking sensation in his gut.

"However we must?" McCoy echoed before looking to Spock. "Say, what did you mean by 'necessary concessions'?"

Spock tilted his head in a way that Bones chose to believe was sympathetic.

"In Coridan culture, only women are allowed to practise medicine," he stated succinctly.

It took Bones a moment to make sense of what was being implied.

"You want me to pretend to be a woman?" he yelped. "Oh no! No, no, no!"

"Come on Bones," Jim cajoled. "It won't be that bad."

"No," Leonard said firmly before pleading, "Why can't another ship go? One with a female CMO? They're not that rare you know."

"The Enterprise is the only ship carrying the requisite supplies within a reasonable distance to the Coridan system," Spock answered.

"Whose side are you on anyway?" McCoy snapped.

A raised eyebrow was his only response to that before Spock continued.

"In fact their monomorphism will make the pretence easier. You will only need to make adjustments to your attire and mannerisms."

"Oh! Only!" McCoy crossed his arms defensively.

"It's not that big a deal Bones," Jim replied before standing swiftly. "And it's not up for discussion. We'll reach the Coridan system tomorrow afternoon."

He headed for the door followed by Spock. McCoy sat stewing at the briefing room table. Jim halted in the doorway to look back.

"Get Nyota and Christine to help you," he said more gently before grinning like a Cheshire cat. "They'll get you looking like a Southern Belle.