Also in today's Globe: hospital switch, DSS support, autism rates, birth defects and fertility aids

Beth Israel Deaconess Medical Center and New England Baptist Hospital will work together on a suburban expansion. Tufts-New England Medical Center had planned to build a $300 million suburban hospital with New England Baptist but will now proceed alone.

Harry Spence, commissioner of the Department of Social Services, defended how his agency handled the case of 4-year-old poisoning victim Rebecca Riley but said his department needs more medical expertise to help social workers review the diagnoses and drugs prescribed by doctors treating children overseen by the agency. JudyAnn Bigby, secretary of Health and Human Services, said she would appoint an independent physician in the next few days to be on call to help DSS, until the agency develops a medical review system.

About 1 in 150 American children has autism, an urgent public health concern, said US health officials yesterday who reported on the largest study done so far on the disorder. The new numbers, based on 2002 data from 14 states, are higher than previously reported.

Babies conceived through fertility treatments have higher rates of birth defects, but the overall risk is so small that it should not keep couples from having children this way, doctors are reporting.