I love that they call him their second child together. He’s really accepted Leni as his own. As stated before Henry is named after Seal, who’s full first name is Sealhenry. One of his middle names, Gunther, is the name of Heidi’s father.
"Heidi and I are proud to announce the arrival of our second child together. Henry Gunther Ademola Dashtu Samuel, arrived on Monday September 12th 2005 at 7:20PM. Weight on arrival was 8.9 lbs. He measures 21 inches long…Our most treasured moment so far was watching big sister Leni kissing Henry repeatedly on the head. She had been preparing for his arrival for quite some time, pointing to Heidi’s stomach every morning, saying the words ‘Baby, baby."
Source: Access Hollywood