Fact 1 - In 2012 Japan reported a birth rate of only about 1.41. Meaning that the women of Japan gave birth to an average of only 1.41 children during their reproductive years, even lower at 1.09 for women in Tokyo. This is far below the basic replacement rate of 2.1 where long term death and birth rates match for a stable population.
Fact 2 - While the severity was unique at the time, it is not a unique trend. As an area gets more industrialized, its people better taken care of and better educated, the number of average births per woman goes down in a well documented effect.
Fact 3 - While they are scattered all across the industrialization spectrum, every nation on the planet is at least overall moving toward being more industrialized and modernized thanks to improvements in communications and distribution technology.
Fact 4 - In 2032, the birth rate trend has hit even harder then expected as while the population is still a shockingly high 7.7 billion the birth rate officially became lower then the death rate. Not by much, but for the first time in human history since the Black Plague ravaged Europe and Asia in the 1300's overall world population actually went down if only technically in this case.
Fact 5 - There is no mechanism in any time frame, ranging from short term deviations to long term trends, that will stop the decline at a Replacement Rate. In fact there is no mechanism that stops this downward trend at all until a catastrophic failure of at least some social systems occurs.

A bit of history for the reality impaired.
Not many people heard about it, but a some very important people know about those facts. In 2035, most people were just worried about the latest commlink implants, of getting their paycreds on Friday, of how the talks for a Mars colony are going to go. Very few people have put all the facts together, but some of them are very worried. Especially on the official news of what's being nicknamed the MacTobin Effect. Getting cybernetic implants isn't all that weird in 2035, but it messes with your biochemistry. The MacTobin Effect is that getting cybernetic parts can mess with a male body's ability to process certain hormones.
Meaning male cyborgs are less horny then their all-meat counterparts, and their sperm counts take a nose dive. Add to that all the other drama with the birth rates and some very powerful people are worried about the long term implications on the voting populace. Worried enough that some of countries are semi-secretly enacting a solution.
The basic idea being that there's more then one game in town. Cybernetics may drek up male fertility, but there's other ways to modify the human body. Biological modification, ranging from growing and implanting custom biological organs to even tweeking a person's DNA, tends to be much more expensive but it's also possible. It's more expensive to make better Meat parts then it is to replace the Meat with Machines, but it isn't nearly so harsh on the human body.
In fact, some governments and organizations and put two and two together to come up with a plan. Working in semi-secret, some particularly healthy men are being sponsored for biological modifications to go the opposite direction. Some men are secretly being recruited to be modified for the express purpose of getting them to have sex with and impregnate as many women as possible...An idea I had kicking around, basically a less overt version of my GPBL idea.
Basic Premise - In a cyberpunk future, it's been discovered that the already low birth rates have been hit harder by the fact that getting cybernetic implants tends to harm male fertility. To counter this, some countries and megacorporations have gone and alternate route. Using biological modification via custom organ implantation, genetic sculpting, pheromone generators, synthetic genes, and other non-machine changes a small number of men have secretly been modified to try to impregnate as many women as they can in hopes of providing some long term population stability. I'd be playing one of the modified men.
Needless to say, this one will be a wee bit on the smutty side.
Thoughts/Interest/Questions/Comments?