Colin Farrell and his former girlfriend have filed for conservatorship of their eldest son

James suffers from Angelman Syndrome, which according to the pair's court petition is a "a genetic disorder which causes developmental delays and disabilities and affects the nervous system."

Documents obtained by E! news note that James "is nonverbal and has issues with his fine motor skills, making him unable to properly care for his own physical health and well-being and requiring him to need assistance in preparing food, eating, bathing, and clothing himself."

As a result, the teenager's parents want a court to grant them the power to made decisions about his education, control his social and sexual relationships - including whether or not he can marry - access confidential records and grant or refuse permission for medical procedures.

The petition notes that James is unable to express his preference over who he'd prefer to serve as his conservators but his parents "are sure" that if he "could voice his opinion over who he would want" for the role, he would choose Colin and Kim.

A court hearing on the matter is scheduled for 27 September, but James' doctor, Liliana Sloninsky, sent a note to the court advising it would be "difficult" for the teenager to attend because his condition means he suffers with "delayed development, intellectual disability, severe impairment and problems with movement and balance."

She added: "James is non-verbal, gets very anxious and loses his focus easily."

The 44-year-old actor - who also has son Henry, 11, with Alicja Bachleda - previously spoke of how much it meant to him when James walked for the first time shortly before he turned four.

He said: "A child taking their first steps is always such a profound experience. Parents are disgusted if they miss it... Tears can flow, and it's such a huge kind of profound moment in the development of a child's life and in the relationship between a child and the child's parents.

"So when you're told your child might not walk and then your child does walk, two weeks short of his 4th birthday, the absence magnified the presence, when the presence arrived. And in the same way, the absence of certain abilities for our children… magnifies the need for us to all come together."