How can I trace an ancestor's birth if he were "born at sea" in 1830? I think the ship MAY have been from Germany or Ireland and arrived in (possibly) Philadelphia in that year.
I know he went on to marry Catherine Leonard. They lived and died in Pennsylvania (both died in 1855...coincidence or tragedy? They had a son named Samuel K. Linard sometimes shown as Saml Linard, Samuel H. Linard who was born May 9, 1852 in Madison twp, Perry County, Pennsylvania
OLIVE TREE ANSWER: Hi Shirley - if your ancestor were born on board a ship, his name or a record of the birth of an infant would almost certainly be found on the ship manifest.
You're in luck since Pennsylvania archived ships passenger lists as early as 1800. I would begin searching for his parents on Ancestry.com ships passenger lists to America (don't limit your search to Pennsylvania)