A TODAYMoms.com survey finds mothers of three are more stressed than mothers of two or one.
The survey questioned more than 7,000 mothers nationwide.
The biggest cause of stress -- 60 percent of mothers said they don't have the time to get everything done. The same number of moms said raising girls is more stressful than raising boys.
The average mother rated her stress at 8.5 on a scale of 1-10 with 10 being the most stressed.