Dizygote twins, or ¨fraternal twins,〃 are two people resulting from the same pregnancy, but who developed from two separate ova. The ova fertilized by the different sperm cells produce two zygotes that evolve separately. Dizygote twins may be of different genders and have their own genetic code. The frequency of this type of pregnancy is increasing due to fertility treatments such as artificial insemination. It is also higher in certain ethnic groups and in women over age 30.