A wealthy Pfizer exec is fighting to get custody of his girlfriend’s 6-month-old son after the child was taken into state custody in the wake of the mom’s suicide on New Year’s Day, according to court documents.

Child welfare officials took 6-month-old Lincoln from Jonathan Sporn — even though he and the mom were raising the boy as their own — because he is not the baby’s biological father.

Yesterday he edged a step closer to a reunion, as a Manhattan judge ruled he must undergo a home visit before getting custody.

Sporn lived with Lincoln’s mom, corporate attorney Leann Leutner, 40, at his Riverside Drive apartment for more than two years.

They couldn’t conceive naturally and Leutner had in-vitro fertilization with an anonymous sperm donor, the documents explain. The two never married, but Sporn submitted to the court a document appointing him guardian of the child as evidence.

“I am begging this court to assist me in piecing together the shattered pieces of my heart,” he said.