Warning: this Christianity- and Christmas-themed post may offend or disgust. The procedure described is unpleasant for the receiver.
Fertilisation of an egg cell requires sperm to reach it, which does not require breaking the hymen. A thin tube, such as a hollow straw or reed, can be inserted through the small opening in the hymen to pump sperm (obtained via male masturbation) into the vagina. The simplest way to pump the sperm is to suck it into the straw with one’s mouth and then blow it out. Another way is with an enema pump (bulb syringe) that can be constructed with primitive technology: a hollow leather ball glued to a reed using resin, tar or bone glue. The seams of the leather ball can be waterproofed with tar. The ball can be made to spring back into shape after squeezing, e.g. by constructing it with wire hoops or springs inside.
Successful fertilisation with the above method likely requires many attempts, because the probability of pregnancy from unprotected sex during the most fertile part of the menstrual cycle is 30%. Sexual activity causes hormonal changes in the female organism that facilitate fertilisation, which a simple reed insertion probably does not, but it may be possible to create similar hormonal changes with an erotic massage.
The above method can be used to arrange a virgin birth in a primitive society. No miracles are required, although a virgin giving birth may be marketed as miraculous.
Modern in vitro fertilisation technology of course expands the range of ways to engineer a virgin birth.
Tethered balloons are cheaper to install than watchtowers of a similar height, although the day-to-day running cost of a balloon may be higher. Another benefit of a balloon is that its location can be changed much easier than a watchtower’s. A balloon’s advantage over flying drones is the cheaper initial price and running cost.
Cameras and sensors are sufficient for surveillance, so no people are needed to fly the balloon or even be near it (or at the top of a watchtower). The cameras can be powered from the ground, with the electrical cable doubling as one of the tethers, or by solar panels on the balloon, if these can be made light enough. Using infrared cameras, the balloons can help detect forest fires, allow farmers to watch their herd and see predators or large pests (kangaroos, wild donkeys, horses or camels) entering their land.
One possible limitation of a balloon is that in stormy regions it can be blown against the ground and rupture. The tethers can be made strong enough that the balloon does not fly away even in a hurricane, but the tethers are flexible, so cannot push the balloon away from the ground.
Because the balloon is distant from people, it can be filled with cheap hydrogen, despite hydrogen being explosive when mixed with air. The only limitation is if a fire or explosion of the balloon while it is in the air would cause significant economic or environmental damage. Examples are using the balloon for forest fire surveillance in fire-prone regions (burning bits of balloon may fall to the ground), or for watching an oil refinery. The risk of the balloon’s explosion on or close to the ground can be minimised by having an emergency mechanism detect when the balloon loses altitude and vent or explode the balloon while it is still high in the air. For the initial launch and subsequent landing for repairs, the balloon can be temporarily filled with helium or hot air. A thin hose from the ground is needed anyway to replenish the gas in the balloon that is slowly but steadily leaking out. The hose allows replacing the gas in the balloon with a different one.
Electrolysis equipment is probably not light enough to float attached to the balloon, so the balloon cannot produce its own hydrogen from the water vapour collected from the air. If the balloon has a power cable from the ground, then it might as well have a gas hose also. Again, a hose can double as a tether.
Some of the downsides of automatic transmission in cars are that it does not anticipate hills or overtaking, and does not respond to slippery conditions appropriately. The technology that could enable the transmission to anticipate hills or overtaking is already available and incorporated in some cars, namely GPS, maps and sensors that look ahead of the car. If the map data includes altitude, then the location and movement direction of the car on the map predicts the slope that the car will be on in the near future. This information could be sent to the automatic transmission to enable it to shift gears in anticipation of a hill. A forward-looking sensor that has a range of a few hundred metres can also see a hill if the road does not curve too much. The sensor data could also be sent to the transmission. Similarly, a sensor could detect the nearing of the car in front and shift to a lower gear to prepare to accelerate for overtaking.
Slippery conditions can be predicted using the car’s thermometer, perhaps with the addition of a humidity sensor, or detected using a wheel slip sensor. This information could also be sent to the computer controlling the automatic transmission, to prevent it from spinning the wheels too fast when there is little grip. The GPS or forward-looking sensor could also tell whether the car is moving relative to the landscape. Comparing the movement data with the wheel spinning speed reveals whether the wheels are slipping.