Fatty ovaries can upset embryonic development and lead to failed pregnancies, research suggests.
The findings, from a study on cow eggs, support advice to women to avoid being overweight if they want babies.
They may help explain why obese women and those with diabetes often struggle to conceive, say researchers.
These individuals tend to metabolise more stored fat, leading to higher fatty acid levels in the ovary.
The study involved exposing eggs from cows to high concentrations of saturated fatty acids.
The scientists are applying for funding to carry out further studies of human patients. They also want to find out whether exposing eggs to high levels of fatty acids leads to post-birth effects.
Girl (4) dies in pitbull attack
A four-year-old Australian girl has been killed inside her Melbourne home by a neighbour's escaped dog.
The pitbull crossbreed entered the home where Ayen Chol was watching TV with other children and attacked.
A five-year-old girl and a 30-year-old woman were also injured. The dog is to be destroyed and charges are being considered against its owner.
US drones on way to Libya
The US military has sent two more armed Predator drones to the Libya conflict in response to requests from commanders seeking more intelligence-gathering capabilities.
Defence officials said the additional drones will give commanders more flexibility as well as the ability to have several unmanned aircraft in the air at one time to cover more ground.
President Barack Obama approved the use of armed drones in the Libya conflict in April.