Is it permissible to undergo a medical examination to determine the sex of the fetus, male or female, or is that a sin?

It is permissible to undergo a medical examination to determine the sex of the fetus (male or female). This is one of the means Allah has made easy for us to learn about the condition of the fetus after its creation, while certain unseen matters remain known only to Allah, such as its state before creation, its provision, its lifespan, its happiness, and its misery.