Iterating through cur and cur.fetchone()

Hi, how do I use cur.fetchone() when iterating through a cur object.

with
conn = psycopg2.connect()
cur = conn.cursor()
SQL = ('select * from something limit 1000')

n = 1
cur.execute(SQL)
for edge_list in cur:
edge = cur.fetchone()
print n

n = n +1

I get
n = 500

when I skip edge = cur.fetchone()

for edge_list in cur:
print n

n = n +1

n = 1000

Why does this happen, and what is the solution?

--
Håvard Wahl Kongsgård