Twin pregnancy, but due to two different men cause is -

Ref:Synopsis of Forensic medicine and toxicology (K.S.Narayan Reddy) 28th edition, page no.208 Superfactation or Superfecundation means the feilisation of two ova which have been discharged from the ovary at the same period, by two separate acts of coitus commited at sho intervals. The incidence of twin pregnancies is about one-and-half percent and of these, about 70% are binovular twins resulting from separate feilisation of two ova formed in the same menustral cycle.