Gov. Jim Doyle announced plans Wednesday to invest nearly $750 million to support human embryonic stem cell research and other medical experiments.

The governor wants to use a combination of public and private money to build two research centers and support scientists studying infectious disorders, cardiovascular illnesses and Alzheimer's disease.

Doyle, a Democrat, said the proposal would build on nearly $1 billion the state has spent on high-tech facilities during the past 15 years.

"Other states, like California, are trying to play catch-up and build from scratch what we already have," he said.

Californians voted Nov. 2 to spend $3 billion in state money over the next 10 years on stem cell research, counteracting a Bush administration policy that has sharply restricted federal funding for research that involves the destruction of human embryos.

Parts of Doyle's proposal are subject to the Legislature's approval, but the governor can begin some projects on his own.

Doyle said the state's contribution to the proposal would be significant, but he did not know what portion would come from tax dollars.

Embryonic stem cells form in the days after fertilization and can turn into any tissue of the body. Many scientists hope to harness them to grow replacement tissue to treat spinal-cord injuries as well as diabetes and other diseases.