Never, because it will make many of your readers think about semen and wonder whether you're sexist. Pick a word that doesn't have as much baggage and which also more specific to whatever you mean. For example you could say it was influential, foundational, or fundamental.

Note that all the above is true even if seminal doesn't have that connotation to you, and even if you think that it's not sexist language. These are points where reasonable people can and do disagree. But either way you're going to distract some nontrivial number of your readers from the actual point you're trying to make, and that's not effective writing.

Update: I just want to point out that this is not a new issue that I made up. Here's the British Sociological Association including it among a dozen or so words it recommends sociologists avoid (most of the others are chairman and the like). Here are some other people complaining about this usage of seminal. I've certainly heard people at the joint meetings grumble about the unfortunately named "Steele prize for seminal contributions to research." Anyway, as I said I don't think this is as clear a case of sexist language as say chairman, but it is a usage that many people don't like and which has few advantages. It's easier just not to use it.

Never, because it will make many of your readers think about semen and wonder whether you're sexist. Pick a word that doesn't have as much baggage and which also more specific to whatever you mean. For example you could say it was influential, foundational, or fundamental.

Note that all the above is true even if seminal doesn't have that connotation to you, and even if you think that it's not sexist language. These are points where reasonable people can and do disagree. But either way you're going to distract some nontrivial number of your readers from the actual point you're trying to make, and that's not effective writing.

Update: I just want to point out that this is not a new issue that I made up. Here's the British Sociological Association including it among a dozen or so words it recommends sociologists avoid (most of the others are chairman and the like). Here are some other people complaining about this usage of seminal. I've certainly heard people at the Joint Meetings grumble about the unfortunately named "Steele prize for seminal contributions to research." Anyway, as I said I don't think this is as clear a case of sexist language as say chairman, but it is a usage that many people don't like and which has few advantages. It's easier just not to use it.

Never, because it will make many of your readers think about semen and wonder whether you're sexist. Pick a word that doesn't have as much baggage and which also more specific to whatever you mean. For example you could say it was influential, foundational, or fundamental.

Note that all the above is true even if seminal doesn't have that connotation to you, and even if you think that it's not sexist language. These are points where reasonable people can and do disagree. But either way you're going to distract some nontrivial number of your readers from the actual point you're trying to make, and that's not effective writing.

Never, because it will make many of your readers think about semen and wonder whether you're sexist. Pick a word that doesn't have as much baggage and which also more specific to whatever you mean. For example you could say it was influential, foundational, or fundamental.

Note that all the above is true even if seminal doesn't have that connotation to you, and even if you think that it's not sexist language. These are points where reasonable people can and do disagree. But either way you're going to distract some nontrivial number of your readers from the actual point you're trying to make, and that's not effective writing.

Update: I just want to point out that this is not a new issue that I made up. Here's the British Sociological Association including it among a dozen or so words it recommends sociologists avoid (most of the others are chairman and the like). Here are some other people complaining about this usage of seminal. I've certainly heard people at the joint meetings grumble about the unfortunately named "Steele prize for seminal contributions to research." Anyway, as I said I don't think this is as clear a case of sexist language as say chairman, but it is a usage that many people don't like and which has few advantages. It's easier just not to use it.