I found a Theodore Major in the 1850 US Federal Census in Solebury Twp., Bucks Co., enumeration date 31 Aug 1850:

John Major, 35, farmer
Mary Major, 35
Anne E. Major, 8
Theodore Major, 6

All were born in Pennsylvania.

I've attached the image of the census page below.

Source Citation: Year: 1850; Census Place: Solebury, Bucks, Pennsylvania; Roll: M432_758; Page: 180; Image: 361.

Source Information:
Ancestry.com. 1850 United States Federal Census [database on-line]. Provo, UT, USA: The Generations Network, Inc., 2005. Original data: United States of America, Bureau of the Census. Seventh Census of the United States, 1850. Washington, D.C.: National Archives and Records Administration, 1850. M432, 1,009 rolls.