1.   Some Swedish scientists doubt that the nuclear phase-out target can be met without resorting to natural gas.

2.   Although many scientists doubt that the vaccine will protect against infection by itself, some say it may be useful when combined with other types of vaccines.

3.   But many scientists doubt that a killed-virus vaccine is the best way to achieve those goals.

4.   But some scientists doubt that they can cause disease because unlike other infectious agents, they contain no genetic material.

5.   But some scientists doubt the current technology is good enough to catch anybody.

6.   Despite the fact that there may be more planets capable of harboring life, some scientists doubt that intelligent life has ever evolved.

7.   Few scientists doubt that there are genetic differences between groups, but many say any division of Homo sapiens into four or five discrete groups is arbitrary.

8.   Many political scientists doubt it.

9.   Most scientists doubt that any such compounds exist.

10.   Scientists doubt it ever existed.