26 day cycles -- lmp jan.27 -- would conception occur if intercourse were to happen between feb. 21-22?

Of course: Anyone having intercourse without birth control or condoms may get pregnant. Trying to time intercourse around ovulation to avoid pregnancy has an incredibly high failure rate. Use Plan B if this happened and you are wanting to avoid pregnancy. It must be used within 72 hours. Another brand called Ella (ulipristal acetate) can be used within 5 days.