1.   As part of a study aimed at creating a contraceptive vaccine, they were trying to stimulate antibodies against mouse eggs, which would make the animals infertile.

2.   But when they tried injecting the dead sperm into mouse eggs, it failed thousands of times.

3.   Goto decided mouse eggs were too fragile and instructed his student to use bull semen and cow eggs.

4.   Here, our mouse egg is handblown, and a pipe cleaner has been inserted into the egg as a tail.

5.   In a separate experiment, the team matured mouse eggs inside the channels, then fertilized them by squirting sperm over them.

6.   In the study, researchers removed DNA from mouse stem cells and inserted it into a mouse egg that had been stripped of its DNA.

7.   Lacham-Kaplan used the technique to fertilize mouse eggs in a laboratory using cells from an adult female mouse and developed embryos up to five days old.

8.   Scientists found that a substance that blocks one of these proteins kept doxorubicin from killing mouse eggs in the test tube.

9.   The DNA from the cells was removed and inserted into a mouse egg that had been stripped of its DNA.

10.   Then they removed the nucleus from a mouse egg and replaced it with a nucleus from one of the skin cells.