This is very off topic but what about transgenders? That's still a male/female entering the opposite sexes toilets. That's more accepted because that person is usually recognized as being the correct sex for the toilets they are entering. So a male could still be entering the toilets that you're using but you are none the wiser. I don't really see then why it should be unacceptable for a dad to bring his daughter into the female toilets. I don't think he would be pacing up and down the cubicles looking like a pedo scaring everyone who's walking in afterwards. I think most would wait at the cubicle door or at the entrance. If questioned it wouldn't be hard for him to explain he was waiting for his daughter. I think *most* women would be ok with that.
In saying that though I would just want my dh and dd to be comfortable. They would have to make the decision between themselves if/when that situation occurs.