has it been proved

[pigslayer]

that u can breed for certain morphs and then throw new males with female or vice versa and make another morph in the same year

 

[acpart]

I don't know if there are any studies that have been done, but it's likely that new sperm (from a new male) will be more likely to fertilize eggs than the old sperm. The best bet, if someone wanted to to that, would be to re-mix the pairings so the outcome made it perfectly clear which gecko is the father.

Aliza

 

[J.P.]

that u can breed for certain morphs and then throw new males with female or vice versa and make another morph in the same year

first, you can pair the male with many females. but the female is capable of sperm retention, so logically most of the original sperm will be first in line to fertilize the eggs.

second, simply putting in a new gecko will not guarantee that you will get "drastically" different morph. because the offspring of the first and second pairing will share genes since they are "half-brothers/sisters".

a possible scenario is this: you now have an albino pair, then suddenly buy a normal female to pair with the male. by this, you will get albinos from the original pair, then get normal het albinos from the second pair. technically, the hatchlings are different morphs being albino and normal, but still very closely related.
the same thing will happen if you currently have an albino male with normal female, and then buy an albino female.

 

[Riverside Reptiles]

that u can breed for certain morphs and then throw new males with female or vice versa and make another morph in the same year

You would want to wait until you were certain that the female was done laying from that breeding. Then introduce the new male. The female might lay one or two clutches from the first male. Or she might lay for 6 months. There's no real way to control that aspect other than to perhaps cool her down.

 

[TM Geckos]

If it is possible with ball pythons(breeding with two males of different morphs and obtain this two different morphs in one clutch) I think I remember it is not possible with leos.