¿Derecho o recto?
Estoy seguro de que he oido 'recto' o 'todo recto' to mean straight ahead.
My girlfiend tells me that this sounds like it has something to do with rectum and is not correct.
What is the deal here, is it a regional thing or simply incorrect?
10 Answers
I think it's correct, and in fact I usually say things like:
"siga usted todo recto y luego tuerza a la derecha"
"siga derecho" would sound to me like "stand upright" or similar 
From Rae:
9 f. Línea, dirección recta. La recta esbelta del acueducto
10 f. Tramo recto de una carretera, camino, línea férrea, etc.
11 f. Geom. línea recta.
Real Academia Española © Todos los derechos reservados
Almost every word has more than just one meaning. In this particular case, the Dictionary of the Real Academia (RAE) registers eight different meanings of recto, among them, the two you mention in your question: as a right direction, and as the final trait of the gut ending in the annus.
http://buscon.rae.es/draeI/SrvltConsulta?TIPO_BUS=3&LEMA=recto
So saying recto, or todo recto, with the meaning of straight ahead is absolutely correct, both in Spain or in America, as in this sentence:
Quo vadis, Europa? Pues todo recto y a la izquierda… hasta el final!
Quo vadis, Europa? Well, straigh ahead, and then to the left till the end of the road!
http://www.laurarobles.es/?p=513
¨todo recto¨would be straight ahead. ¨Todo derecho¨also. At least in México.
Recto and derecho can also means ¨straight´´ ´´upright´´ or without curves or deviations.
If you go to the translator here it will give you the usage of the word ¨recto¨´
Well, it seems, the use of "recto" as a noun is the rectum, but the use of it as an adjective means straight.
In Mexico, if someone is giving you directions for example to go straight ahead, "Derecho, derecho" and "Todo derecho" are very common.
"Recto" is used more for things such as "Después de la reparación, se quedó recta la pared del edificio ."
Thanks all, it seems then that it is correct but that usage varies with geography.
My parents are coming to visit me in Bogotá soon and my step-dad is fully learning Espanish and I'm helping him with the process. Alto cinco to him!
Seems that today he is learning directions 
In the Rocket Spanish course I am taking we had a lesson on directions and they used both recto and derecho. The author of the lessons is from Chile.
When I initially started to learn Spanish, for about about three years in 1975, the phrase for "straight ahead" was "todo seguido".
"Vaya todo seguido - continue straight on".
I don't know whether this phrase is still used today.
Derecho does mean go straight, but the cab drivers here are so used to bad accents that they'll ask if you meant to turn if you look American, because they don't think you know the difference between derecho and derecha. Sigue and gire are pretty much always understood for go straight and turn, so those are the words I normally use.
Perhaps the person said "todo directo" so quickly that it sounded like "todo recto."
