Sources tell ET that one of Charlie Sheen and Brooke Mueller-Sheen's newborn twin sons, Max, is still in the hospital with a heart condition.

Max and his twin brother Bob were born March 14. The couple, who married in May of last year, announced last October that two babies were on the way. Sheen has three daughters -- Sam, 5, and Lola, 3, with his ex-wife Denise Richards -- and 24-year-old Cassandra from a previous relationship with ex-girlfriend Paula Profitt.

He recently spoke to ET about his newborns to our Mark Steines, saying, "It's pretty amazing. Not a whole lot of sleep, but what parent does at this stage? There's adrenaline, excitement, fear."

Keep checking back here for more on this developing story...