I never read that passionfruit has male and female plants, but someone told me that's the case and that the male have fruit but much less, which seems to me very strange. Is this true?
Your informant was missinformed. The Passionfruit family have both male and female parts on their flowers. Maybe your informant was thinking of Paw-paw/Papaya
You can work this out if you know a bit about how the plant received it's name. The plant was introduced from the New World into Europe in about the 18th century. A religious scholar thought that the flower provided an excellent way to demonstrate the crucifixion of Christ (ie. the passion of Christ). The five anthers (part of the male reproductive organs) represent the 5 wounds. The three styles (part of the female reproductive organs) represent the 3 nails. The five sepals and five petals together represent 10 out of the 12 apostles (Peter and Judas are not included). The five sepals making up the calyx can also be interpreted to represent the nimbus or glory surrounding Christ's sacred head. The three large flower bracts represent the Trinity. The hand like leaves and the whip like tendrils represent the hands and the scourges of Christ's persecutors.
Passioflora species are often dioecious, although the common passionfruit that we normally grow in australia is self polinating. The rootstock if you allow it to grow is almost guaranteed to be male, although I have seen a female rootstock sprout when I was in melbourne.
