Was Anna Nicole Smith's Daughter Damaged by Her Mom's Drug Use?

Oct. 20, 2009— -- The father of Anna Nicole Smith's daughter said that a prosecutor in the drug trial of Smith's former boyfriend tried to strong-arm him and suggested he "ramp up" his testimony to claim that his daughter would have developmental problems due to Smith's drug use, even though he said his 3-year-old daughter is fine.

In a hearing Friday, Birkhead said Smith was admitted to a drug detox center at the Cedars-Sinai Medical Center four months into her pregnancy. But before his testimony resumed Monday, Birkhead said a prosecutor approached him and suggested that he claim his daughter, Dannielynn Hope, would have developmental problems due to Smith's drug use.

"I was there for the prosecution, but I don't think they liked what I had to say. So I feel like it turned. They were trying to beat me up in the end, but the truth is the truth," Larry Birkhead told the celebrity Web site TMZ.com.

Smith, a former Playboy Playmate, died from an overdose of prescription drugs in February 2007.

"A prosecutor cannot dictate to a witness what that witness should be saying -- after all the prosecutor should be on the side of truth and justice, wherever that lies," attorney and legal analyst Dana Cole told ABC News.

Birkhead's testimony was part of a preliminary hearing to decide whether Smith's former boyfriend, Howard K. Stern, and two doctors will go to trial on felony drug charges related to her death.

Birkhead told TMZ that the prosecutor also accused him of taking Stern's side.

Stern previously tried to gain custody of Dannielynn but lost after a DNA test proved Birkhead was the father.

Larry Birkhead Says Daughter Dannielynn Is 'Healthy'

In court Birkhead admitted that after their daughter was born he filed a paternity suit and asked that a drug test be performed on the baby because of Smith's prescription drug use, according to the Associated Press.

"Whenever a mother takes something that alters her mental state it's bad news for the unborn child. Even if a child at 2 or 3 or 4 years old is showing no problems, it doesn't mean they're clear in the future," said Dr. Lisa Thornton, a pediatrician at the Comer Children's Hospital at the University of Chicago.

Birkhead says his daughter is fine and shows no sign of developmental problems.

"She's very smart, she's very healthy and happy," Birkhead said about 3-year-old Dannielynn. "I've been told by several doctors she's quite advanced."

Birkhead said the prosecutor crossed the line when she suggested he imply otherwise.

The Associated Press contributed to this report.

CLICK HERE to return to the "Good Morning America" Web site.