BOSTON — The Legislature yesterday swiftly overturned Gov. Mitt Romney's veto and approved a bill designed to propel Massachusetts to the forefront of embryonic stem-cell research.

The bill immediately became law over Romney's objections, after both chambers exceeded the two-thirds vote needed to override a veto.

Under previous state law, scientists who wanted to conduct embryonic stem-cell research in Massachusetts needed the approval of the local district attorney. The new law seeks to expand stem-cell research by removing that requirement but giving the state Health Department some regulatory controls.

The Republican governor vetoed the bill last week because it allows the cloning of human embryos for use in stem-cell experiments, a practice Romney said amounts to creating life in order to destroy it.

Romney has said he supports research using either adult stem cells or cells extracted from leftover frozen embryos from fertility clinics.

The new Massachusetts law bans cloning that results in a baby. While President Bush has imposed limits on federal funding for embryonic stem cell research, no law has been passed by Congress that specifically bans reproductive cloning.

Supporters of embryonic stem-cell experiments hope to transform Massachusetts into a center for cutting-edge research into the cure and treatment of spinal-cord injuries and diseases such as diabetes and Parkinson's.

The bill does not include any funding for the research, but Senate President Robert Travaglini, a Boston Democrat, said the Senate may consider devoting taxpayer money to the research in the future.

In Connecticut, the state House of Representatives overwhelmingly voted yesterday to approve legislation that would endorse and fund embryonic and adult stem-cell research in the state.

The bill would pour $100 million over 10 years into the evolving research, and set up guidelines and advisory panels and a peer review board to advance and regulate the research.

The legislation has been a top priority for both the Democrat-controlled General Assembly and Republican Gov. M. Jodi Rell. The Senate has already approved it, and Rell has committed to signing it.