U.S. President Barack Obama released the long-form version of his birth certificate on Wednesday, identifying the Hawaii doctor who delivered him.

Karl Sinclair, son of Dr. David Sinclair, said his family was "blown away" and "honoured" to learn that the late obstetrician had delivered a baby who had become president.

David Sinclair's signature is underneath Obama's mother's signature on the long-form birth certificate that was released Wednesday.

According to Karl Sinclair, his father delivered babies across the state of Hawaii at the time of Obama's birth. The elder Sinclair died in 2003 at age 81.

Obama released the long-form version in an effort to stop the ongoing "silliness" about where he was born.

Conspiracy theorists and even Donald Trump have raised doubts about whether Obama was actually born in the United States, which is a requirement for all U.S. presidents.

The certificate released on Wednesday says Obama was born in Honolulu, Hawaii, at Kapiolani Maternity and Gynecological Hospital on Aug. 4, 1961.

Speaking at a brief news conference on Wednesday, Obama said the certificate was released because the issue was beginning to distract attention away from important issues such as unemployment, America's debt and high gas prices.

"We do not have time for this kind of silliness, we've got better stuff to do, I've got better stuff to do," Obama said. "We've got big problems to solve and I'm confident we can solve them but we're going to have to focus on them, not on this."

He said he realizes that no matter what evidence is put forward, there will be a segment of the U.S. population that refuses to believe he was born on American soil.

After the certificate was released, Trump, who has hinted he may launch his own presidential bid, said Obama should have released the document a long time ago.

He also took credit for the fact the certificate was finally released and put a positive spin on the development.

"I am really honoured, frankly, to have played such a big role in hopefully, hopefully getting rid of this issue," Trump said in his own news conference.

The long form birth certificate is signed by the delivery doctor, Obama's mother and the local registrar.

The form says the child was born at 7:24 p.m. on Aug. 4, 1961.

The father is listed as Barack Hussein Obama, age 25, who was African and born in Kenya. It says his mother was Caucasian and born in Wichita, Kansas.

Hawaii's registrar certified the new photocopy of the document provided to the White House on April 25, 2011.

Obama had released the short form of his birth certificate -- a legal document that residents of Hawaii receive when they request proof of their birth -- in 2008. However, he sought out copies of the long form certificate this week as so-called "birthers" have continued to question where he was born.

Polls show that a significant number of Republicans continue to believe that Obama was not born on U.S. soil and therefore not eligible to serve as president.

During his news conference, Obama laid some blame on the media for continuing to cover the issue, which he considered settled.

"This issue has been going on for two, two-and-a-half years now. I think it started during the campaign," Obama said. "I have watched with bemusement, I've been puzzled at the degree at which this thing just kept on going."

Obama went on: "We're not going to be able to solve our problems if we get distracted by sideshows and carnival barkers."

Many Republican lawmakers have stayed away from the birther debate. After Obama's news conference, Republican National Committee Chairman Reince Priebus issued a statement in which he criticized Obama for discussing the issue.

"The president ought to spend his time getting serious about repairing our economy," Priebus said. "Unfortunately his campaign politics and talk about birth certificates is distracting him from our number one priority -- our economy."