In The Sims Mobile you can only create an adult Sim at the beginning of your play. In this production, Sims can be infants, young children, children, adults and elderly (pensioners). There are no teenagers or young adults in The Sims Mobile. To procreate, you need to get to know a person from your surroundings. This person doesn't have to live in your home or be associated with your character.
To adopt or conceive a child you need to have level 3 romantic relationships with another Sim and level 11 of experience. You cannot buy a cradle until you have this level of experience. If you already bought it, just click on it. There will be a few options to choose from. You will be able to either try to get a child with someone or adopt them. There is no need to wait for the child, after a while a small family member will appear in the cradle.
The difference between adoption and conceiving a child is that you may choose the sex of your child during the adoption process.
The child is not a playable character. To control this young Sim you need to wait until he/she grows up and become an adult. In addition, you must have a free slot in the family. Sim doesn't have to take care of his child. It does not need to be fed, washed or put to sleep. It is enough to have an event with your child once a day. In this way, it gains points of character that will create a trait when it grows up. This feature will allow him/her to gain experience faster at work. The child grows up after some time, regardless of the player's actions .
You can have a child with person of any gender, of any age. The only condition is to have a level 3 romantic relation.