Well... It is a serious illness, And although I agree I don't like your use of the word 'admit', I think it's ok that you are questioning things and thinking it through.
Firstly, a third of people who have a schizophrenic episode never have one again. A third have occasional episodes, and a Third live with it through their lives. Obviously having children with someone in the first box is a different prospect than someone in the third. I think you need to talk about how many episodes your partner has had, and how long he has had this illness.
People who are having a schizophrenic episode often have delusional thoughts, or hear voices, or have unusual or paranoid beliefs. They may create / find themselves in vulnerable situations because of this. It would be hard for them to work, care for kids etc while I'll. But remember anyone can get I'll - it's the same kind of issues you'd be facing if you were with someone with diabetes or heart disease - it might rear its head, it might not.
The meds for schizophrenia are powerful, and can have unpleasant side effects, including sexual side effects. If your partner is on meds long term it might be worth discussing.
Finally - SOME people think there may be a genetic vulnerability to schizophrenia whic could mean some people could inherit an increased risk of getting the illness. That does not mean your children would get it but it might mean that in certain circumstances their brains might be more vulnerable to a schizophrenic episode. This is a controversial issue, and not everyone thinks there is a genetic factor.
Remember through all this your partner must be a good man who you like if you have been together 6 months and considered children. He is not just a diagnosis. Many people are with partners with health problems - and you could marry a healthy man tomorrow, only to find him diagnosed with cancer next week. So consider the whole person - not just the schizophrenia - when you think about the future of your relationships.
My stats came from mind (mental health charity) - here