What is the meaning of “eugenics”? I googled in the internet and when I read I couldn’t understand. It says “eugenics” is not practiced nowadays. Why is that so? I simply couldn’t understand anything about “eugenics”. Please help me without beating around the bush.

Thanks in advance.
In a few words, it’s when the powers that be control the number and composition of the general population (mess with how humans multiply). For example, they can surreptitiously put something in the food to lower the probability of fertilization to decrease the human population.