The survey wasn't designed to determine causes but is useful in assembling a "more complete picture of autism" and in helping communities plan services for children, said Coleen Boyle, director of the CDC's National Center on Birth Defects and Developmental Disabilities.

WSJ: Autism Diagnoses Up Sharply

Last month, the National Transportation Safety Board said federal investigators had not been able to determine the causes of fires in two plane batteries or the electrical shorts that occurred.

CNN: STORY HIGHLIGHTS

The trial will determine the causes of the spill, and assign responsibility to the parties involved, including BP, Halliburton, Transocean, and Cameron, which manufactured the blowout preventer meant to stop oil leaks.

BBC: BP: Gulf of Mexico oil spill 'shared responsibility'

In 2005 I met with the then Executive Director of the PBGC and senior staff to propose that the agency conduct forensic reviews of bailed-out pensions in order to determine the causes of failure.

FORBES: PBGC Probes Wall Street's Role In Pension Failures

We want to see the entire picture and not focus on individual events, to determine the root causes of these events.

FORBES: Boeing's 787 Dreamliner Public Relations Nightmare: A Battery Of Problems

The teams will review patient records and lab results and question health workers and patients to try to determine the cause or causes.

CNN: Army hunts cause of pneumonia in troops

Mr Atwood told Good Morning Ulster that the investigation would look at issues including fraud and procurement to determine whether there were "any further causes for concern".

BBC: Attwood expects Red Sky report in 3 weeks

"What we have learned is that there is not enough information to determine either that the handling of irradiated mail causes these symptoms or that it does not cause these symptoms, " Green said.

CNN: Report calls for more study of irradiated mail

If that confounding variable can be taken care of, though, and the effect persists, the next obvious step is to determine what mechanism within the mother's body causes the discrepancy.

ECONOMIST: Poor circumstances breed daughters