Gender by Blood Renewal
This folk theory says blood 'renews' every 4 years in men and every 3 years in women. Enter the dates and see its guess. Just for fun.
For fun only. This is not accurate and cannot tell you your baby's sex or traits.
General information only, not medical advice. Ask your doctor or midwife.
How this works
Formula: Mother: age ÷ 3, father: age ÷ 4. Whoever has the smaller share of the cycle used up has 'younger' blood, and the baby is guessed to be that parent's sex.
- The calculator works out each parent's exact age on the conception date.
- It finds how far each parent is into their 'renewal' cycle: 3 years for the mother, 4 years for the father.
- The parent who is earlier in their cycle has the 'younger' blood, and the method guesses the baby will be that parent's sex.
- The idea that blood renews on a fixed 3 or 4 year clock is not true. Blood cells are replaced all the time.
- This is a folk method shared for fun. It is not accurate and cannot tell you your baby's sex. Only medical tests, such as an ultrasound or a blood test, can do that.
Everything is worked out in your browser. Belly Weekly does not send or store your answers.
Questions
Is the blood renewal method real?
No. It is a folk belief. Your body replaces blood cells constantly, not on a set schedule.
What if I recently had surgery or a blood transfusion?
Some versions of the folk method restart the clock after major blood loss. It does not change the fact that this is just for fun.
What actually decides a baby's sex?
Whether the sperm carries an X or a Y chromosome.