Brooke Mueller has agreed to have her sons tested for ''fetal alcohol and drug syndrome''.

The 36-year-old troubled star - who has four-year-old twins Bob and Max with 'Anger Management' star Charlie Sheen - will reportedly have her two young children tested to see whether they have mental and physical defects which can develop in a foetus due to high levels of alcohol consumption during pregnancy.

It is believed the Los Angeles Department of Children and Family Services (DCFS) thought it was a necessary move and Brooke - who went to rehab twice while pregnant due to her addiction to crystal methamphetamine - wants to cooperate.

Sources told ''Brooke did indeed also drink large amounts of alcohol while pregnant. This was on top of the drug use which included meth.''

Another source confirmed: ''[Child services demanded] Brooke sign off on having the boys tested and assessed for fetal drug and alcohol syndrome.''

This comes after another of Charlie's ex-wives, Denise Richards - who was granted temporary custody of Bob and Max in May until the end of this year - wrote to the DCFS to inform them she can no longer care for Bob and Max as they are violent towards her own children and dogs.

The actress - who has two daughters, Sam, nine, and Lola, eight, with Charlie, as well as an adopted daughter Eloise, two - also included photos taken before and after they had visited Brooke on July 26, with the later picture showing a large red mark on Bob's head.

The source explained: ''Denise's letter outlining the disturbing and violent behavior of Bob and Max prompted the agency to force the issue because Brooke had been steadfastly against it in the past.

''The good news is that they will now be properly tested, and monitored.

''It will be crucial that DCFS follows up and follows through with whatever the testing reveals. The boys' lives literally depend on it.''