Translation guide
The English word "sperm" can refer to the male reproductive cell or to semen. In Japanese, these are distinct words, and the context (biology, medicine, everyday conversation) determines the best choice.
Referring to the microscopic reproductive cell that fertilizes an egg.
The standard biological/medical term for a sperm cell. Used in formal and technical contexts, as well as in everyday conversation when discussing reproduction.
精子は卵子と受精する。
Sperm fertilizes the egg.
精子の数が少ない。
The sperm count is low.
An older or more colloquial term for sperm cell, literally 'semen bug'. Rarely used in modern scientific contexts; may appear in older literature or informal speech.
精虫が卵子に向かって泳ぐ。
The sperm swim toward the egg.
Referring to the fluid containing sperm, ejaculated during orgasm.
The standard term for semen in medical, biological, and formal contexts. Also used in everyday conversation.
Loanword from German 'Samen', commonly used in casual and slang contexts, especially in sexual contexts or adult media. Considered informal.
Loanword from English 'sperm', used in some technical or older medical texts, but less common than 精液. May also appear in some adult contexts.
スペルマの質を調べる。
Examine the quality of the sperm.
精子 (seishi) refers specifically to the sperm cells, while 精液 (seieki) refers to the seminal fluid as a whole. In English, 'sperm' can mean either, but in Japanese, the distinction is important. Use 精子 when talking about fertility, count, or motility; use 精液 when talking about the fluid itself.
While スペルマ is understood, it sounds dated or overly technical. In most contexts, 精子 or 精液 is more natural. ザーメン is common in informal sexual contexts but may be inappropriate in formal settings.
ザーメンを飲む。
Swallow semen.