Male humans have a different genetic structure from females, consisting of an X and a Y chromosome, where females have two X chromosomes. The genetic difference accounts for various differences...
sperm
No. Some may be sterile. On a side note, there is no such thing as a female sperm. All sperms derive from males and needs to move to female's egg.
Any sexual contact (genital, oral, anal) will transmit chlamydia.