| Ovarian tumor histology (World Health Organization classification) | Incidence of bilaterality (approximate %) |
| Serous cystadenoma | 12 to 23 |
| Serous borderline tumor | 55 |
| Serous carcinoma | 60 |
| Mucinous cystadenoma | 5 |
| Mucinous borderline tumor | 5 |
| Mucinous carcinoma | 5 |
| Mature cystic teratoma (dermoid) | 15 |
| Dysgerminoma | 15 |
| Other malignant germ cell tumors | 1 |
| Granulosa-stroma cell tumor | 5 |
| Secondary tumors | 70 |
