1.   Researchers speculate that this area becomes overloaded and shuts down eventually, leaving the woman numb and clinically depressed.

2.   Anger is known to increase heart rate and raise blood pressure, which some researchers speculate may injure blood vessels.

3.   As they become older and are forced to cut back, researchers speculate, other obsessive behaviors will take the place of the weights.

4.   At a emergency conference held there last month, researchers speculated that water pollution, radiation or ozone depletion could be throwing frog development into upheaval.

5.   Because baby fireflies are not mature enough to reproduce, researchers speculated that the larvae might use light cues for survival instead of reproduction.

6.   For years, researchers have speculated that rainforest monkeys use plants as painkillers, antibiotics, or even hallucinogenics.

7.   Keen and other chocolate researchers speculated that plant chemicals calls flavonoids are behind the perceived benefit of chocolate.

8.   No one knows why, but the researchers speculate that when the mice moved in the magnetic field it somehow disrupted their balance systems.

9.   Other researchers speculate that some birth defects might have an unrecognized link to infertility.

10.   Researchers speculate that this may be caused by a combination of genetics, diet and a reluctance to get medical checkups.