Does the role of men and women change?

[YaKuZA]

As i noticed in the apartment over the antique shop, julia and winstons roles are very odd...he is scared of the rat while she says she'll patch it up. But why did they change?

[Ana Lovejoy]

Since 1984 is a dystopia, maybe the change of roles can be one of the negative aspects (such as the antisexualism) that Orwell uses to emphasize the distortion of the society.

[Granny5]

I think it just means that Winston was afraid of rats. I'm afraid of spiders so my husband takes care of getting rid of them, my husband is afraid of wasps so I take care of getting rid of them. I didn't read anything else into that, except that it gave BB a way of knowing that Winston was afraid of rats.

[KurtDunn]

I honestly believe that portion of the book was just to more humanize the two characters.

It's a little more like real life, not some stereotyped sit-com where the woman always cowers while the man shrugs and gives a vaguely comical confused frown as he hammers out the pest. Some guys are terrified of the things too.

Plus it's a great way to foreshadow room 101.

[The Atheist]

As i noticed in the apartment over the antique shop, julia and winstons roles are very odd...he is scared of the rat while she says she'll patch it up. But why did they change?

As noted, this is all about how the Thought Police learn of Winston's phobia. No role changes take place - there may have been a reason Orwell chose rats. I suspect it was because of the imagery of the rat-cage attached to his face at the end, but I wouldn't bet money on it.
:)