At the ultrastructural level, the sperm head contains condensed to granular chromatin with large open spaces between the chromatin. Fetuses with congenital heart disease CHD show evidence of Narrow headed sperm brain development before birth, which is thought to contribute to adverse neurodevelopment during childhood. Stallion Normal morphology Abnormal head Abnormal midpiece Narrow headed sperm tail Proximal cytoplasmic droplet Distal cytoplasmic droplet T1 Assessment of chromosomal abnormalities in sperm of infertile men using sperm karyotyping and multicolour fluorescence in situ hybridization FISH. Intyracytoplasmic sperm injection in men with totally immotile ejaculated sperm. First drawing of mammalian spermatozoa by A.