|Post-testicular factors decline male fertility due to conditions that affect the male genital system after testicular sperm production and take account of defects of the genital tract as well as problems in ejaculation: Vas deferens obstruction Lack of Vas deferens, often connected to genetic markers for Cystic Fibrosis, Infection, e.g. prostatitis, retrograde ejaculation, Ejaculatory duct obstruction, Hypospadias, Impotence.
The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.