the first thimg you should know is- infertility means unable to concieve even after one year of unprotected regular Sex. If that's the case it may be due to numerous causes, in womens- it might be due to uterine abnormality,hormonal imbalance, fibroid in uterus,sometimes infection like T.B would have scarred fallopian tube which might be a cause,certain medications, obesity etc. In men- decreased sperm count, chronic alcoholism,smoking,obesity,premature ejaculation,medications, testicular infection or trauma etc.so get this things checked. You should know that there are 20-25% cases where the cause is unknown for infertility.As I already mentioned if you are not concieving for more than one year, you can try invitro fertilisation(IVF) technique which has a good sucess rate.kindly consult a obstetrician regarding this.