diff --git a/R/check_data.R b/R/check_data.R
index 6fd4e56..81572a2 100644
--- a/R/check_data.R
+++ b/R/check_data.R
@@ -8,6 +8,7 @@
 
 
 check_data <- function(dat, sex = FALSE, showPlot = TRUE) {
+  if(sex) stop("Cannot currently handle sex structure, set to FALSE")
 
   ## header checks
   colheads <- tolower(names(dat));names(dat) <- colheads
diff --git a/R/refit_Growth.R b/R/refit_Growth.R
index dcddb98..e9a1a1d 100644
--- a/R/refit_Growth.R
+++ b/R/refit_Growth.R
@@ -13,7 +13,7 @@
 #' @export
 
 refit_Growth <- function(dat = simulated_data, breakpoints, selex = FALSE, showPlot = TRUE){
-
+  if(selex) stop("Cannot currently handle selectivity, input must be FALSE.")
   if(any(is.na(breakpoints))) stop('Cannot handle NA in breakpoints. Did you mean to use +/-Inf?')
   # Apply the function to each row of df2
   split_tables <- purrr::map(1:nrow(breakpoints), function(i) {