Sentence:  Scientists say the birth is the second confirmed instance of a shark being conceived by <WSD>parthenogenesis</WSD>, a process in which an unfertilised egg develops into a new individual. 
Meaning of the word marked with <WSD> tags:  (An instance of) reproduction by the development of a single gamete (an ovum or ovule) without fertilisation by a gamete of the opposite sex; compare (metagenesis), (heterogamy).