Also found in: Medical, Encyclopedia, Wikipedia.


The entry of several sperm into one ovum during fertilization.

pol′y·sper′mic adj.
References in periodicals archive ?
The effects of sperm--egg ratios on polyspermy in the blood clam, Tegillarca granosa.
Fertilization in fishes and the problem of polyspermy.
In teleosts, the cortical alveoli content is released into the perivitelline space, at the moment of fertilization, blocking polyspermy and contributing to chorion hardening (Hart, 1990).
A teleost egg is covered with a thick envelope called a chorion, which has a narrow pore designated as a micropyle that helps to avoid polyspermy [15].
Parrish [30], states that the number of sperm added to oocytes during IVF affects the percentage of oocytes penetrated and even increase polyspermy rate.
The quality of matured oocytes is decisive for the fertilization rate, as a result of sperm penetration and complex oocyte changes including cortical granule exocytosis-prevented polyspermy and oocyte activation for embryonic development [6-8].
There were more cortical granules in the cortex of oocytes in the HDE group, which may prevent polyspermy process.
To avoid the fatal consequences of polyspermy, female reproductive tracts have evolved to become formidable barriers to sperm.