I pulled these photos off the last.fm fan list of a certain infamously horrible metalcore/deathcore band. It's up to you to determine each specimen's sex.
Some of these are quite tricky.

1-3, 6, 9, 11, 12, 14 are guys or close enough to count.
4, 8, and 15 are legally girls
5, 7 and 10 are future guests on Maury "Which of these had a sex change?"

1. Male
2. female
3 M
4 F
5 M
6 M
7 F
8 F
9 M
10 M
11 M
12 M
13 F
14 F
15 F

1. male
2. male
3. female
4. female
5. female
6. male
7. female
8. female
9. male
10. female
11. male
12. male
13. female
14. female
15. female

...maybe. There are chest-bumps on #15 that are probably breasts. >_>

1 m
2 f
3 f
4 f
5 f
6 m
7 m
8 f
9 m
10 f
11 f
12 m
13 f
14 f
15 f

1. Male
2. Female
3. Male
4. Female
5. Female
6. Male
7. Female
8. Female
9. Male
10. Male
11. Female
12. Male
13. Female
14. Female
15. Female