Charlie Sheen's ex-wife Brooke Mueller reportedly agreed to test the couple's twins for fetal alcohol syndrome following news that the 2-year-old boys have exhibited alarming behaviors.

Mueller consented to the testing after Child Protective Services received a letter from the boys' former guardian, Sheen's other ex-wife Denise Richards, saying she could no longer care for the boys, Max and Bob.

Richards had been caring for the twins in addition to her daughters with Sheen -- Sam, 9 and Lola, 7, -- as well as her adopted daughter 22-month-old Eloise. She began caring for the Mueller's boys in May after the latter's ongoing battle with substance abuse landed her back in the hospital. 

Richards wrote the DCFS recently saying she could no longer care for Max and Bob because of their violent behavior against her daughters, resulting in the girls being strangled, kicked in the head, bitten, slapped and punched.

Mueller's brother, Scott, was granted temporary guardianship of his nephews on Nov. 9.

The twins are now being tested for the disease because it could be a root cause of their behavior. Mueller, 36, famously checked into rehab twice during her pregnancy for an alleged addiction to crystal methamphetamine. She reportedly also received treatment for alcohol abuse at the time.

Fetal Alcohol Syndrome is one of the potential results of a woman drinking during pregnancy, according to the CDC, The spectrum of disorders that fall under the disease are 100 percent avoidable if a woman completely abstains from drinking alcohol during pregnancy.

"When a pregnant woman drinks, the alcohol goes across the placenta to the fetus via the bloodstream," Dr. Raja Mukherjee said on his Drink Aware website, which also warns of the dangers of drinking during pregnancy. "The fetus's liver isn't fully formed, so it cannot metabolize the alcohol quickly enough."

A fetus that is exposed to alcohol that tests positive for Fetal Alcohol Syndrome is placed potentially at risk for hormonal disorders, epilepsy and cerebral palsy.

Mueller gave birth to her boys seven weeks premature and they were forced to stay in a Neo-Natal Intensive Care Unit due to weak heart conditions. If they do test positively for Fetal Alcohol Syndrome, it could mean Mueller risks losing custody of her son.

Tags: Charlie Sheen Brooke Mueller child custody battle