A sperm is said to be amorphous with a pinhead shape when it's impossible to differentiate between the head and the midpiece.
This pinhead malformation is severe because these sperm don't have genetic material inside their head. Therefore, pinhead sperm cannot fertilize an egg.
Read the full article on: What Types of Sperm Morphological Defects Exist? ( 72).

Marta Barranquero Gómez
B.Sc., M.Sc.
Graduated in Biochemistry and Biomedical Sciences by the University of Valencia (UV) and specialized in Assisted Reproduction by the University of Alcalá de Henares (UAH) in collaboration with Ginefiv and in Clinical Genetics by the University of Alcalá de Henares (UAH).
License: 3316-CV