baby guppies - male vs. female

[omaha_frisbee]

My female fancy guppy had about 25 babies about 4 weeks ago, which are separated and protected. I was hoping to keep the males and give away the females. However, it looks like all of the babies are female. Is this possible? Or do they morph a little more later on to show the different phenotype?
Thanks for any help you may send.

 

[grimlock3000]

Your chances of getting 25 females and no males are close to 0. Some fry take longer than others to show their sex. Usually by the time you can tell, the males have already mated with the availible females as well

 

[Menagerie]

Some fish do have offspring of only one sex, but I do not believe livebearers fit in that category.