set.seed(1234)
n  = 4
mu = 1
a  = rnorm(n, 0.0, 1)
b1 = rnorm(n/2, mu - mu/4, 1)
b2 = rnorm(n/2, mu + mu/4, 1) # interaction is mu/2

dat1 = dat2 = data.frame(Group = c(rep("C", n), rep("T", n)),
                         Sex   = rep(c(rep(0, n/2), rep(1, n/2)), 2),
                         Val   = c(a, b1, b2))

# Now male is the reference
dat2$Sex = ifelse(dat2$Sex == 0, 1, 0)

fit1 = lm(Val ~ Group*Sex, dat1)
fit2 = lm(Val ~ Group*Sex, dat2)

# Results
dat1
dat2

summary(fit1)
summary(fit2)