25-year-olds Jennifer Granberg and Christopher Harris each pleaded "not guilty" to one count of murder.
The couple is accused of killing Granberg's son, 2-month old Alexander Xavier Frett on Sunday.
During the hearing Christopher Harris appeared to be crying as he held his head down.
The public defender cited a conflict of interest with Harris but will be representing Granberg.
The attorney asked that a mental evaluation be performed on Jennifer Granberg.
Police say Alexander Frett was found not breathing on Sunday and appeared to have suffered from severe burns from water.
The suspects will be back in court at the end of this month.