You have been selected by the governments-funded World Research Facility to raise one of the 1st-generation power users, known as Ascendants. These beings are theoretically mankind's best defense against the Great Invasion, a global catastrophe that was made known through deciphered signals from outer space.
As of now, only weeks-old babies born from the laboratory have been "given" powers, because a more grown-up human is more complicated to modify. The researchers had planned to raise them in a controlled environment and monitor their daily living. However, they considered the possibility of the Ascendants developing negative personalities due to living as test subjects rather than actual humans. That's why you were selected, along with several other people.
As per written in the official contract:
You are to be registered as the young Ascendant's guardian and will raise them for as long as you feel like.
The government will anonymously provide you financial support to an extent, if it's needed for raising the young Ascendant.
Once they are of legal age, they will be recruited by the government for official training and combat against the otherworldly invaders.
You are forbidden from telling the young Ascendant about their origins as a lab-created experiment, or they'll likely develop an identity crisis.
You may request a specific superpower to give the Ascendant. However, due to insufficient research, powers that are too incomprehensible for human understanding are unavailable.
If the Ascendant is able to use their power competently and cooperate with other Ascendants to repel the otherworldly invaders, you will be granted the same power that they possess (once that technology has been perfected).
If the Ascendant is proven to be unwilling to cooperate during their recruitment, or even show signs of malicious intent toward human society, a remote-controlled device implanted somewhere in the Ascendant's body will be activated. It is capable of depriving them of their power at best, or causing permanent damage or even death at worst.
What power would you give your Ascendant child? And how will you raise them so that they'll be competent and ready for their actual purpose in the future?