Nothing strange about that. It probably means that there is only one toilet available, which can be used by either males or females - not at the same time of course! ;o}
If we were to beleive the movies to be real life anyone would think toliets in US service stations are only place murderers and serial killers hit maybe they get confused by the signs too??
or...was the station down the road from a sex change clinic?? It would be like peeing next to mr or mrs potato head with bodily oddments stuck on here there and everywhere..otherwise know as ....optional extras
whenever i've used the ''bathroom'' in the US as you will be aware i've never seen a bathtub so why oh why do our American friends call it The Bathroom ( perhaps Clanad will answer this) also please note that if the term ''Multi-Gender'' becomes prevalent here you will all have to learn to pronounce it ''Mul-tie'' not ''Mul-tee'' Ron. LOL. Ô¿Ô
Comparably in UK we have uni-sex toilets - which actually mean 'one' sex, not both.
'Bi-sex' toilets could have unfortunate connotations, as could an American 'multi-sex' loo...........it's a di-lemma ;o)