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Rabbits/genders and genetics


I have been breeding rex rabbits for one year now, my problem is that I get more male kits then female (about 80% ). Is this genetic from one of the parents or is this just nature. I would love to hear your opinion on this. Thank you

Dear Marjie,

It's impossible to say why you are getting such a high proportion of males without more information.  Getting 80% males is not outside the realm of probability, though this percentage should decrease with a larger sample size unless something weird is going on, genetically.

It's possible, though not highly likely, that the female babies have a greater likelihood of inheriting a harmful allele of a particular gene that's on the X chromosome than the males.  This is possible in the case of an X-linked dominant allele, but this should be expressed by the parent carrying it unless s/he has a genetic "hot spot" on that gene that is constantly mutating during formation of eggs or sperm.

How big is your sample size?  Are the litters small, in general?  If so, then it's possible that males are also inheriting the X-linked dominant, but they are not viable, either.  

In human families, some people are predisposed to having sons or daughters.  Again, this could just be a matter of probability.  But we've all heard of some families in which "sons run in the family" (or daughters).  In such cases, it is possible that the female reproductive tract is somehow more hospitable to sperm carrying a Y chromosome (which are smaller and faster) or to an X chromosome (which are heavier, but last longer than X-carrying sperm).  

There are a LOT of possibilities here, not least of them simple chance.  But the most important information I can share with you about breeding is here:

I hope this helps.



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Dana Krempels, Ph.D.


I've lived with companion rabbits for more than 35 years, and consider them members of my family. I can answer any questions about the biology and health of rabbits, from the commonplace to the unusual. But please note:

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For all the best, most accurate rabbit health, care and behavior information, visit The House Rabbit Society.


I have been rescuing and rehabilitating domestic and wild rabbits for about 30 years. I have written articles for many rabbit rescue publications, as well as for the veterinary journal, Exotic DVM. I own EtherBun, the internet's largest listserve dedicated to health, care, and behavior of domestic rabbits.

Houserabbit Adoption, Rescue, and Education, Inc. (H.A.R.E., Inc.) president National House Rabbit Society (Board member)

Exotic DVM
Warren Peace (Journal of the House Rabbit Society of Miami)
Various newsletters of the House Rabbit Society, nationwide

Ph.D - Biology
B.S. - Biology
B.A. - English

Awards and Honors
Lightspan Academic Excellence Award for web site on rabbit health and biology

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