Gender question

Kelsie • Navy spouse. ⚓️🇱🇷. Momma to a beautiful little boy 9.17.17. 👪. TTC baby 2 now. 🤞🤞

Isn’t there a blood test you can do early on to determine the gender of the baby? I would love for my husband to be home when we found out. I’m currently 4 weeks and he leaves in August for deployment.