The Home Office respects family ties and allows you to bring your family to the UK on almost any visa.
On a UK Graduate Trainee immigration route, you can add the following family members to your application:
A spouse or a civil partner if you prove that you have lived together for at least two years (photos and utility bills will do).
Children younger than 18 years old at the time of application. If a child is over 16 years old, you will have to prove that they live with and are dependent on you.