It happened five years ago, their is a vaccine now, 9 out of 10 treatments are effective. But at that time their was nothing. People everywhere were effected and the world changed.
It all started with US military researchers secretly trying to develope a bioweapon to disrupt morale of insurgents in the middle east. The strong gender divisions in fundamentalists their were theoretically exploitable by a gender altering virus.
The virus was far from perfected when the terrorists turned the tables. A traitor within the lab slipped them a sample, they were going to smuggle it on a plane to unleash on the US. They were caught, but not before the virus was released at a major airport. At the time the US was tight lipped on their experiment and no one knew what it was, or was aware of is long incubation period, so no one properly quarantined it after the first few people appeared to show no symptoms. From that airport the virus went global.
Within a few weeks the virus's symptoms were being felt. The majority of people had merely mild flu like symptoms though occaqsionally with odd side effects like changes in eye or hair color. But 4 out of 10 people experienced more than that. 3 of those 4 experienced partial gender change effects as their body fought off the virus before it could finish. the remaining quarter of those with noticable effects had full gender changes.
The changes were mostly physical. In fact whether any mantal changes at all occured is uncertain. Their was a rise in bisexuality and crossdressing after the event but whether this merely resulted in people adapting to changed lovers and bodies is unknown. Even most full gender changed people dress like they did before the change and keep their original gender identity.
