[R] "xtable" results doesn't correspond to data.frame

[Vumani Dlamini]

Dear useRs,
Am trying to use xtable on the following data.frame and I don't get what I 
expect:

example.table <- data.frame(rbind(
    c("Gender"," "," "," "),
    cbind(rep(" ",2),c("Male","Female"),c(3.0,4.0),c(3/7,4/7))
))
colnames(example.table) <- c(" "," ","number of patients","%")
example.xtable <- xtable(example.table)
print.xtable(example.xtable, include.rownames=FALSE)

I can seem to get latex output which corresponds to the data.frame which is,
\begin{table}[ht]
\begin{center}
\begin{tabular}{llll}
  \hline
  &   & number of patients & \% \\
  \hline
Gender & &   &   \\
    &  Male & 3 & 0.428571428571429 \\
    &   Female & 4 & 0.571428571428571 \\
   \hline
\end{tabular}
\end{center}
\end{table}