diff --git a/pyplink/pyplink.py b/pyplink/pyplink.py
index 41458f3..dc4844a 100644
--- a/pyplink/pyplink.py
+++ b/pyplink/pyplink.py
@@ -231,7 +231,7 @@ def _get_seek_position(self, n):
     def _read_bim(self):
         """Reads the BIM file."""
         # Reading the BIM file and setting the values
-        bim = pd.read_csv(self.bim_filename, delim_whitespace=True,
+        bim = pd.read_csv(self.bim_filename, sep=r"\s+",
                           names=["chrom", "snp", "cm", "pos", "a1", "a2"],
                           dtype=dict(snp=str, a1=str, a2=str))
 
@@ -333,7 +333,7 @@ def get_duplicated_markers(self):
     def _read_fam(self):
         """Reads the FAM file."""
         # Reading the FAM file and setting the values
-        fam = pd.read_csv(self.fam_filename, delim_whitespace=True,
+        fam = pd.read_csv(self.fam_filename, sep=r"\s+",
                           names=["fid", "iid", "father", "mother", "gender",
                                  "status"],
                           dtype=dict(fid=str, iid=str, father=str, mother=str))