The 1861 census on Findmypast, household transcription, has:
Name Relation Condition Se x Age BirthYear Occupation Where Born
COSTAIN, Robert Head Married M 42 1819 Roper Castletown Isle of Man
COSTAIN, Ann Wife F 41 1820 Peel Isle of Man
COSTAIN, Ann Elizth Daughter F 15 1846 Dressmaker Castletown Isle of Man
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RG number:RG09 Piece:4416 Folio:102 Page:1
Registration District:Isle of Man
Civil Parish:Conchan Douglas Municipal Borough:
Address:2, Culloden Place, Conchan Douglas, Douglas County:Isle of Man

Official civil birth regt started in 1878, so mainly only parish records before then.

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